title: Episode 11: TOP 10 MEDICAL QUESTIONS ABOUT DIVING
author: DIVE TALK
contenttype: podcast
publication: DIVE TALK
published: 2020-05-16T10:52:17-04:00
sourceurl: https://traffic.libsyn.com/secure/divetalk/Episode_11.mp3?dest-id=1756346
word_count: 15178
Welcome to dive talk episode 11 last episode we focus on sharks got pretty good feedback on that a lot of people didn't know I didn't know when I talked to William and to you or Bill and I I I mean that it was mind blowing like some of the facts that we discovered on the episode Well, you know how I feel the world does not survive without sharks true in entire world I'm pretty serious about that absolutely whole another conversation, but that was the gist of that show I also think they have special magical healing powers Which is gonna kind of tie into this topic well? Yeah, so as we talk to our Incredible guests like we're honored to have this guest. We're gonna introduce him in a minute I'm gonna bring in the other healing powers that I think are going on You may not fit all of the proven science yet All right, that science will come that will up. It'll catch up to me Absolutely. Yeah, I mean that that same I think approach to a fact-based episode from the last episode about sharks Is something that I want to continue on this episode because I have questions I have questions about Use medical questions about diving that I feel like I can never get a straight forward answer I hear like recommendations and is best practice to this or that but I never can get the straight up answer to my questions We will today so we figure we invite Doug ever soul to the show welcome Thank you so much great to be here. Thank you for joining us You've been listening to the show since the first episode you always provide amazing feedback so we're really really happy to have you here and You know see if you can help us with some of this questions, but before I start with questions Let's talk about you like how come You know you get to do all of this dive focus medicine because one thing that I really love about you is when you hear About these doctors like you know the basketball teams have doctors team doctors and football teams or those doctors never actually play basketball A football like at the level of those athletes, but you are actually a world class diver yourself Which makes this unique you're a diver and a doctor talking about dive medicine So can you talk a little bit about yourself when do you start diving? How do you get here? Yeah? I started diving in 1974 and high school and then Went on to college in the medical school took a break while I was doing training and Texas and so forth and then got back into diving in 2000 so I've been diving another 20 years after that um I got I'm a cardiologist by trade. That's what I do for a living so um With cardiology training and then being an active diver I do I start out recreational diving like everyone else I started technical diving around 2002 and got into rebreaters around the same time and started teaching closer-cute rebreaters and technical diving try mix and so forth around 2005-ish So I've been doing a lot of technical dive in myself technical dive training rebreather training and so forth for probably 15 years um, and then with my medical background and the diving experience I started getting lots of questions From the dive community either phone calls or emails are just sitting around you know having to be or after diving or something Um, and I contacted divers work network and I started working with them probably 10 or 12 years ago It's I'm a volunteer. I don't get paid by them, but I I'm more of their cardiology consultants so I probably get two or three at least emails or pms via scuba board or a cave diver form or something every week with some aspect of dive medicine So uh in combination with that I got in with a couple of organizations to do dive medicine training around the world And so kind of excuse to go diving so My wife and I have traveled to bonair multiple times to Fiji to Sakura and so forth on dive medicine trips where I was on faculty so I've done that Uh, and I've been fortunate enough to speak at Dima at EuroTech at OzTech Uh tech dive USA all those sorts of things so it's like anything else in life the more these things you do the more you get known And the more you get asked to do and it just kind of snowballs from there absolutely but the knowledge Check off the qualified Sure, absolutely check and we got rid of that the qualified right But the knowledge not only comes from going to school But it's from doing it yourself and I assume I mean those five years when you get back when you got back into diving in 2000 By 2005 you were trying to make some structure. I mean those were pretty intense five years I guess yeah, we uh what actually happened is I've been diving through The late 80s from early 70s to the late 80s and then took a break from medical school and family and so forth so we had actually gone snorke we got a windsurfing trip actually to Aruba and my wife and I did some snorkeling with the kids She said to be more fun to actually go scuba diving so I said I can handle that So we got her back in a diving the following year our daughter who was 12 at the time got served on who I think I know at least what he knows Very well And then our son when he turned he would when she was 12 he was eight So he did scuba rangers And then we got him certified at 10 and then with all four of us diving it we just kind of took off So there lots of recreational diving myself and I started getting into more the technical stuff by myself And then our daughter who would he knows very very well was Woody's a re-breather instructor She is a try mix CCR diver and a CCR instructor That's awesome I wonder how much like equipment and just the world diving change during your break Right from the from the early 80s to the 2000. I mean it was nine in the I assume Yes, I mean when I started diving was basically when Woody started diving so it was like steel 72s and and J valves no spgs I'm out of air. Yeah, I think Yeah, no no bcs, you know nothing that kind of stuff no dive computers obviously the only thing we had kind of in the late 70s to early age was the deco meter the scuba row had the deco meter which was Coloc we called the bendo-matic It was just an oil pressure thing and it would the fall of you when it would kind of go up towards 30 or 40 feet Saying stop there. It'll it moves this way back down to 30 feet or 20 feet or 10 feet. It was Yeah, kind of crazy. Oh the wheel came along remember the wheel I have to figure out line this up line that up and You should be okay even though you're not really gonna be at that depth the whole time anyway. Yeah That's awesome, but one thing I don't think it has changed since the 70s or 80s till now is The way our bodies react to diving and physics doesn't change exactly exactly So I do I wrote my top 10 medical questions about diving things that I'm wondering that I've been wondering for years And I promise I wasn't gonna google this stuff I wanted to wait until we recorded this episode and we talked to you so I can react live to your answer So let's just get right to it right so question number one is One of the things that I love about diving would re-breatheers is the the fact that we don't have to Do a service interval like you don't have to come up after 45 minutes take a break and then go back down Or whatever you can die for like four hours in a row like there's no Doesn't like the limit is kind of set by the sore live and all their aspects of it And they got so you have and whatnot But surface intervals are doesn't seem to be as important when you're diving You know with re-breatheers versus open circuit like with open circuit You die for like an hour or whatever and then you have to spend an hour on the boat And then you can go back down and not probably do the same dive It has to be like a smaller quote-unquote dive So can you talk a little bit about the science of surface intervals? Why is it so important for open circuit but not as much for closed circuit? Okay, it's all about the physics so Whenever you're breathing compressed gas You're gonna have some component of that as oxygen which you metabolize And some component of that is gonna be inert gas which you don't metabolize So the inert gas is what gets taken up by tissues for regular air diving or nitrox diving that's nitrogen For trimax diving it also includes helium But for the sake of this argument we're talking about it being nitrogen. So that would be nitrogen loading so The higher the percentage of Oxygen that you're breathing the lower the percentage of nitrogen that you're breathing So if you're breathing higher concentrations of oxygen for whatever reason whether that's diving nitrox versus Air or diving a CCR versus nitrox you're going to be loading less nitrogen So if you're loading less nitrogen then you can stay down longer before you go into required decompression And you will have less nitrogen to quote off gas on the surface than somebody else So that's why those things occur as an example With the re-breathers because you brought that up If you think of air diving for say 60 feet Okay, you can use 60 feet for about an hour on open surface Yeah, yeah, and then you got to come up and then off gas That's your no decompression limit on air obviously. That's a little bit longer on nitrox for exactly what we talked about because you have higher oxygen levels You have lower nitrogen levels you're loading less so you could have longer dives or shorter surface intervals Right, if you're diving a re-breather with a Set point a PO2 of 1.3 your no decompression limit Okay, is two and a half hours Okay, so yes You could do a two and a half hour dive at one time as opposed to a 45-minute dive followed by a surface interval followed by a 45-minute dive You could spend the whole time underwater because your nitrogen loading is so low Compared to that so it's all about physics One of the example that Woody always likes to we talk about with re-breathers is if you think about diving on air Okay, so you finish your dive And you come up to the surface so you're now at one atmosphere of pressure and you're breathing the atmosphere So you're breathing 21% oxygen and 79% nitrogen So your partial pressure of nitrogen at that point is 0.79 So whatever you have in your tissues is going to move as a gradient whatever's higher than that's going to move It's going to off gas against that number of point seven nine. That's the gradient If you're on your re-breather, okay, and you are at 20 feet which is 1.6 total atmospheres and your breather is set at a PO2 of 1.3 Okay, that means all that's left for nitrogen is 0.3 So your partial pressure of nitrogen rather than be 0.79 on the surface is 0.3 at 20 feet so you're actually much better You're much more efficient. You're much more off-gassing. You're much safer Okay, from a decompression standpoint to stay on your re-breather at 20 feet Then you are to come up to the surface and sit on the boat and breathe air That's what I love. I just want I just want us I can stay there. I make the argument I'm just gonna stay under where I want to be at 20 feet And then you're even better off not just Better off, but then you're even better off if you're gonna like catch a flight Just literally stay at 20 feet Top up if you could magically snap your fingers and get on there plan to be better off Interesting because I do have questions about flying after diving. All right, so that's awesome So thank you for that all right So question number two and this one came kind of after The episode that we did about diving for women or you know, we had Terry on the episode and we talked about kind of diving from a woman's perspective and going pro and all that stuff But you know one of things that I thought about after that episode is what happens to pregnant women right something that I'm not concerned about at all, but for women, you know, how does can a pregnant woman dive like that? That's number one. How does that affect the baby and essentially inside The baby cannot equalize right? So how does that affect that and what if they don't know like especially early on the pregnancy like one month pregnant two months They don't know what could happen if they go diving without knowing right there's um Actually been some observational studies on pregnant women diving the by the way the the The quick answer is pregnant women shouldn't dive That's that's the first thing But because of risk to the to the fetus Not saying they should abort a pregnancy if they find out they've been diving pregnant But once you discover that you're pregnant people the women should stop diving The reason behind that is for so I talk about the equalization Equalization is not going to be much of an issue because all the fluid all the air spaces that we have are going to be full of fluids And fluid doesn't compress so that's not as big a issue the bigger issue is is the nitrogen loading so what happens to a fetus Um, if you are if the mother is loading nitrogen scuba diving that is then going through the placenta to the fetus and what happens to them More importantly how well or poorly do they off gas as the mother to be is ascending Okay, and God forbid what happens to a fetus if a mother has a decompression illness What are the effects to the child and how do you treat that person in a chamber because now you're treating two people not one person So that's the real reason for not doing it The observational studies has been a couple of these done. I won't go to all the details I have them if anybody had a question, but it's usually a few hundred people and they've looked at whether or not There were women who continued to dive during pregnancy or women who did not and what happened to the fetus um There's been two older studies There were more women diving during their pregnancy choosing to continue to dive during pregnancy. Wow More recent data women have stopped so they've learned from Dan and other people should do that There were some incidences of bizarre things like um fetuses being born without a hand Concern of a possibly an error theoretically maybe an air embolism kind of issue um There've been lower birth weights in Japanese pearl divers who dive all the time dive right through their pregnancy So there may or may not be a higher incidence of spontaneous abortion There may or may not be a higher incidence of birth defects There may or may not be a higher incidence of low birth weight But the feeling is it's not worth the risk We're again not saying that women who find out the pregnant should abort the pregnancy clearly not It says you should be as cautious as you can so if you're a dive professional dive master and dive instructor um And become pregnant then you should stop diving Yeah, just take a break right from diving Easier said than done when that's how you make your livelihood But that's that's the medical answer. Okay. Well, that's good to know Anything to add witty you're good. I mean just logically speaking. I can't imagine they You know these dive computers and dive tables are built for understanding what's happening to a a fetus so uh they're tiny their Blood movement and so forth and so on so just even step it away from the science. It's just logic says that you know I mean we don't know how the decompression models work on a fetus that's developed that's in development stage So I wouldn't do it just for that when the word I don't know gets into diving right I would pause Yeah, and the other issue which is not part of this talk, but there's what's called patent frame on ovality Which is a flap in the heart A fetus has that on purpose because they're not using their lungs so the oxygen That's going from the placenta into the right side of the heart doesn't get filtered by the lungs like it would with you and I It goes directly into the left side circulation So any venous bubbles from ascending that you and I would probably have filtered by our lungs Hopefully in a fetus it's definitely going to go across a patent frame of ovality in the systemic circuit to get Embellized to brain spinal cord Vital organ so you'd worry about that as well. That's just normal physiology for a fetus. Yeah Yeah One last one last thing on that so once this woman has her child then like next question should be you know when can they go back right Yeah, right that is the feeling with after A vaginal delivery is that women should wait at least three weeks and the reason for that is the cervix remains open So you would not want any kind of water intrusion and likely ascending infection So after about three weeks the cervix is completely closed back down and they can resume diving For a cesarean section just like any surgery you'd want to wait four to six weeks Make sure you're completely back to normal everything's healed all the scars are healed and then they can return to diving. Oh, okay Good. Yeah, awesome all right Question number three and this one I guess it depends on a person like I know David one of the guys that we dive with he Doesn't like taking C-Sick medicine I personally like to take it even though it doesn't make me feel great But I'm just concerned about missing a great dive because I'm so sick that I can dive Why do people get C-Sick because you you see the crew members like people to work on boats They're like rock stars like I don't see them taking anything They can be out there in like the perfect storm kind of weather and they're like fine. So How can the boat crew? Do that and I you know and most people I guess struggle with it So can you talk about C-Sickness and kind of your recommendation also to prevent it You know, I'm I'm I brought in some patches into this this dive trip I haven't tried them yet. It's Kapolemina. I guess it's called or right Kapolemina Yeah, we'll talk about that so But then there's drama man. There's ginger. There's there's different things. So what do you use do you get C-Sick? Just talking about that. Yeah, I first thought yes. I'm very prone to get C-Sick my wife doesn't get C-Sick at all I'm very prone to get C-Sick First question is kind of why do we get C-Sick The what happens is our what tells us What's level in our body is what's called the cochlea's in your inner ear? Okay, it looks like a snail shell with some hairs in it. It's all full of oil And it acts as our natural gyroscope so it tells us what's the level so we don't fall down Okay, so we kind of know what's going on The problem is when you're on a rocking boat You're cochlea that inner ear knows you're rocking But if you're walking around inside an enclosed cabin your eyes think everything is fine because everything is moving Along with your eyes. So your brain gets these mixed messages as to what the heck is going on And that's what causes the nausea and the vomiting and so forth So one trick to avoid things is you want to first off be where there is the least motion of the boat Which would be kind of in the center line, okay And Sea level not really high really low so you get a lot of rocking Um, so you don't want to be there Uh, and you'd like to be able to see what's really moving So if you start to get C-Sick you kind of get to the kind of the mid part of the boat get out of a cabin down below And put fixed your eyes on the horizon Because that will if you put your eyes on the rise and your eyes will say wait a minute things are moving up and down So okay, you're not getting the mixed messages your your brain your ears saying yes things are moving your eyes saying yes things are moving You're not getting mixed messages. You'll do a lot better. They're all in agreement Yeah, they're all in agreement Another thing's fumes of stuff can be very bad that can make things worse So staying away from the engine exhaust and so forth is is the second kind of thing with all that for for avoiding it As far as treatment um, there are lots of things out there that work well for some people and don't work well for other people Um, ginger has been shown to be helpful in some people some people use ginger. It works great Uh, most people will require some form of an anti-histamine Um, the common ones are dramemmine, you know or bonin Uh, which is also called mechlasine and those are used for treatment of things like vertigo and so forth Which is another inner ear problem the scopolamine patches are probably the best one that's out there Uh, it's what's called transdurn scope. Uh, it's by prescription the others are not uh, and it lasts for three days So you can put it on and kind of leave it on for a few days Uh, all these things can make you groggy That's just a side effect of anti-histamines and can make you a little kind of you just kind of groggy kind of feel out of it So it's a trade-off Uh, the second thing always is different these medicines affect different people differently So from a safety standpoint, it would be a good idea to try them at home before diving So that if you're starting some funny neurologic symptoms, you get some urinary retention, you get dry them out Some sort of findings that in some cases could be confused with decompression illness You want to know if that happens to you top side or if it only happened on this dive trip so always do it ahead of time Makes sense. What do you do? Well actually just the way he was describing it got me a little bit C6 sitting right here at this table literally I was like sitting here going. I'm all the sudden I'm feeling C6 Here's what I do. I kind of agree with what you said us at the beginning There's no downside in my opinion the groggyness is there But they do make non-drausey dream I mean you may still feel a little bit tired But boy to miss a dive I couldn't handle that so I always tell my students Take one or two the night before and then one in the morning when you wake up of that particular boat Right and then if you're on a liverboard just take just take one every morning when you wake up and I don't really feel the groggyness and most of time most people it'll go away within a couple of days anyway So if you are if you're on a liverboard If you put like one transitoring scope patch on so by day three to take it off you're probably fine Or if you do two or three days of some bonding you're probably get your C legs quote-unquote and that goes back to answering your other question Which is your body will get used to this? So if you're a sailor who's at sea all the time Uh, those people their body kind of learns to adjust to the problem That's why your boat captains in your salty old seamen and the dive masters don't get sick when everybody else is throwing up on the boat Because they're on the boat doing this every day so their body is kind of adapted to it. That's awesome. Oh be cool So I guess we just need to dive more exactly We just need to dive more speaking of ears question number four is still related to ear I think my ears are just bad at or busted or they don't work. I don't know. I don't know But your head's bad. I've always I've always I've had this you know I used to play water polo when I was younger and we used to play at the the dive pool And the dive pool was 30 feet deep Uh or 20 something 24 to 30 something like that and I used to just go down We used to have this challenge where you can you take a water polo ball all the way to the bottom of the pool Because getting to the bottom pool is easy But can you take a ball all the way down and see how small it gets? So you know, we used to do this So my ears kind of got messed up like doing that over and over and over again over the years And I'd realized when I learned how to dive that I never have to equalize like my ears Just automatically equalize like I started going down and my ears are equalizing by themselves Non-stop I can go down to 100 and something feed never have to blow through my nose or do anything not even once So how come that happens to me like it's weird because when I'm with students and I'm being a dive master or whatever I have to pretend that I'm equalizing my ears. So they see me do it. So they do it Right, but I don't need to do it and I when I when I do it I'm pretending that I'm doing I'm not actually doing it because my ears just self equalized Why can't I do that? I don't I don't understand. Okay. That's a very good question It's all about what your anatomy happens to be the the situation there is there is a connection between the back of your throat The the use station tube that goes from your nasal pharynx or the back of your throat into the middle ear And that is a very flushy tube that tends to be kind of open and closed based on lots of different things So what tends to happen is that will have It'll be equalized to let's say to sea level because it's got some air trapped in there But it's now collapsed. So there's some air in there that's at the equivalent of sea level As you're descending and you're now breathing pressurized air in your mouth If this is still sealed well, that's going to start to by boil's law start to decrease in volume And that as it decrease the volume and pulling on thing you start get ear pain. That's what that's what happens So what you have to do is then find some way to get the pressure equalized in that use station tube So you've now breathing ambient air at depth in your throat, but this Tube and most people is partially closed So you have to do something to increase the pressure in your throat to kind of open that tube to allow the air to equalize most people Their new divers that requires a valve salvo. So that's the pinch and blow So the pinch of nose blow and that increases the pressure and allows you to equalize You can also do things you can use your back of your tongue and kind of use like a pile driver You know, there's friends L techniques or other techniques that the that freed divers use And also some people can just swallow and just the action of swallowing generates enough pressure If you're on an airplane is the same kind of problem in reverse And you swallow some of that'll just drink just enough pressure to open it up So my suspicion for someone like yourself is that either some combination of doing this for a long time Or just the way your anatomy is Those tubes are very open or very big or very open and doesn't take much effort If you just by taking a breath and maybe swallowing or whatever else in a pops open and you never have to equalize Other people can have problems with their U station tubes So the equalizing is a nightmare for these people So they have to kind of go down a rope very very slow and every couple of feet They have to equalize or go back up a little bit and so forth And so basically what I tell students is if you don't have problems flying on airplanes with your ears You're probably not gonna have a real major problem diving with your ears If you have a real problem you don't know where you ever get through an airline flight is by You know pinch and blow pinch and blow chewing gum all kinds of stuff in your ears still hurt You're probably gonna have an issue that's weird reason how do you mention? I never thought about I've never feel anything on planes I never have any problems on planes flying or with my ears or anything like that That's kind of odd too This is bringing up another question actually in my mind now that you started speaking when you said the word tube Because my daughter had Tubes put in her ear when she was younger some people have to have tubes put in the air because they're always Having problems with that so would that be a problem and what about people with other things inserted in their body stents I mean I know that's an area you know a lot about is that affected by pressure? No, the area is gonna be with the answer your second question first No, because that's in a fluid filled environment So a vascular stint is in a blood vessel. There's no air space there. So that's not that's not a problem To answer your other question about Tubes nearest from many of these kids this would be kids who get middle ear infections Which are on the other side of the the tempanic membrane the eardrum So they'll have to be opened up and placed tubes to kind of maintain them to stay open to allow things to get that to drain That will tend to heal over time that just be like bursting your eardrums the same kind of concept but in a more controlled Fashion to hear about some of you who's trying to clear there as they burst near drum You got to wait for that to heal it takes a few weeks same thing with tubes once people have had tubes That will usually heal over time. It's very it's reasonable people have to have multiple tubes To kind of make sure before they dive the someone looks in their ears and make sure there's not still a hole there Because that would allow Salt water so for the end of the middle ear and could be at risk for infection one last thing not real common but there are People who just cannot equalize It's not usually for diving but it's more for air travel But innocent throat doctors can actually go with a small balloon into that use station tube And balloon open the use station tube and it's not really the tube itself the changes But the outside cartilage and so forth they can expand that to allow it to be easier for the for people to cool Equus so they can correct it. That's awesome And you know we were talking about flying a second ago and how that affects your ears as well I question number five is also about flying and this is just I mean I get this mixed kind of Best practices about flying I think when I learn on my open water is said When you dive you cannot fly for 24 hours like it's pretty straightforward you dive you cannot fly for 24 hours And I remember learning that and thinking about well, what if you dive like 15 feet 20 feet like is that like I understand if you do 130 feet or whatever, but what if it's pretty shallow It's still 24 hours if you go you know shallow diving Um, then you start reading a little bit more in some agencies will say something like it's 18 hours It's not 24 18 is more than enough Uh, and then some other people say well depends on the dive if you though twice then it's 24 If he's only once 12 is fine, but you get you keep hearing all of these mixed information about Flying after diving and I won the truth. I just want to understand exactly What's happening? What's the problem with flying after diving? Why can I just go diving and then hop on a plane later that day and just go home and Doesn't matter if going home is eight hour fly versus an hour fly like what are the if any if I do do it Am I gonna like what have a heart attack in the plane or just feel like I'm itching like Just tell us a little bit more about the science of flying after diving. Okay, the very good question And it comes up a lot the the issue with flying after diving is simply just like surfacing in a surface interval It's all about the physics so when you Fly That is continuing you're a scent So just like when you are sending from the bottom to the surface You're trying to slowly off gas because you're worried if you come up too quickly You could have bubbles form When you get on a plane you're just continuing that ascent you're now continuing that ascent from the surface to 30,000 feet Okay, now planes aren't pressure planes pressurized to about 7,000 feet 7,000 8,000 feet So really be the equivalent of coming up from a dive and then driving to the top of a 7,000 foot mountain Okay, that's basically what you're doing So you're continuing that off-gassing stress, okay? So you could bubble on the plane and that happened that has happened not in freqonies people get decompression sickness on a plane on their flight home So that's really what you're doing. It's it's a decompression problem. It's not a cardiac problem Anything else. It's a decompression issue As far as how long to wait before flying It's similar to your safety stop. I mean how long do you do a safety stop? Well if you do a 30 40 foot dive you may do a three minute safety stop If you did a 130 foot dive you may say well, you know what? I'll do a five minute safety stop I'll just be a little extra cautious by staying at this level Longer before I continue my ascent, okay? It's the same thing with with flying after diving So what you've done you've made your ascent to the surface How long are you going to do a quote surface safety stop? Okay, so before it's here. Okay before ascending Okay, well just like on your dive is gonna be well how much nitrogen have you loaded? If you haven't loaded much nitrogen Then you probably don't need much of a surface safety stop before flying Whereas if you've loaded a lot of nitrogen then you should probably kind of hang out of the surface for a while Okay, it's the same kind of concept in 2002 diver's net work did a flying after diving symposium Okay, and that's where these data came from So their recommendation on that after that symposium with a bunch of experts quote unquote in the field Giving a expert consensus not on any randomized trials was for a single dive You should wait 12 a single no decompression dive you should wait 12 hours before diving so if you were If you're flying I'm sorry before flying so if you were on a vacation and you just single dive at grand came and you're supposed to fly out You should probably wait 12 hours before flying If you've done multiple days of diving multiple dives of multiple days, which is kind of a typical Uh dive dive trip live aboard. Yeah They'll usually stop you diving at noon the day before you fly out that way if you have a morning flight because the recommendations 18 hours So for multiple Multiple days of diving multiple dives the recommendations to probably wait about 18 hours Which would basically be you could dive the morning of the day before you fly out but probably not the afternoon depending what time your flight's leaving That's kind of what that number comes from and then the recommendation if you do any decompression diving Okay, because again decompression diving by by default you've actually loaded a lot more nitrogen right so If you do any decompression diving it's kind of wait quote at least 18 hours and most people say about 24 hours so usual Guidelines to think is as all master on how much nitrogen loading you've done if you have minimal not loading like a single dive 12 hours Multiple days of recreational diving like most dive trips wait 18 hours If you're a technical diver and you've been doing some decompression diving you should probably wait at least 24 hours before flying Okay, and then the that's I Based on your answer. I assume that the depth of the dive matters So like when you when you dive within 30 feet like if it's pretty shallow You don't even have like the computer says you don't even need it to do a safety stop is like your whole dive was a safety stop So what happens then yeah from a physics standpoint if you're doing if you were doing like the blue hair and bridge like we're planning on doing this afternoon this 20 feet And you dove it for an hour and a half Could you safely fly this evening probably so It questions how it's all a risk versus benefit thing So how much do you want to dive today if you're flying out tonight or do you want to mug your flight tomorrow morning to have one more safety So it's a it's a it's a gambler's all about risks versus benefits the risk there would be very very low So it just kind of goes into thinking what if I ignore whatever like I'm like I don't believe in And you know this this diving restrictions or recommendations I just go out and fly no matter what like I dove on the on the morning Maybe I was out on a truck diving less you know less dive was in the morning I fly in the afternoon what happens okay So you're someone who doesn't believe the world of physics right okay? Don't believe physics don't believe physiology doctors don't know what they're saying that's right okay So you would you would have a Just like with anything else now no dive computer talks are coming up in a sound questions are coming up in a second You can do everything right and get bent you can do everything wrong and not get bent I mean we don't know that much about the exact nature of decompression science But you would be putting your risk yourself at risk for decompression sickness now would that be skin bins Maybe would that be some elbow pain? Maybe would that be a stroke Maybe wow would that be paralysis? Maybe okay, and the problem is if that happens to you on the surface You get sent to a recompression chamber with high partial pressures of oxygen If you have that happen on a plane You're going to get 100% oxygen But you're at 7,000 feet so it's not really going to be 100% right so your treatment is going to be less than adequate So you're gambling that you're not going to have a problem or gambling that you're going to have a minor problem Or gambling that if I have a problem Suboptimal treatment with oxygen will take care of it before the plane can land and get me somewhere so probably not in your best interest And then a question that comes up often Doug saying you're at 7,000 feet When maybe the plane's flying at 30,000 or 35,000 feet remember that air planes for everybody listening out there They're pressurized cabins, but I think the greatest plane now only will pressurize that even down to like 5,000 feet because they're trying to make their customers less tired so That's the issue It's not that the plane's going to lose its pressurization is that it never Is not at least 5,000 feet. Yeah, I think most planes are 8,000 Based on what I And also there is a possibility that you could depressurize too that would be a double bad day But just think about but but just think about that right we're only coming up from what 60 feet 80 feet 100 feet now you're going up another 5,000 or 8,000 feet. I mean how many more atmospheres up. Yeah, so that's that's could be Yeah, that's pretty bad. That's awesome. The other thing to think about that by the way is how do you evacuate somebody who has decompression sickness most planes will probably they'll probably send some you you have to risk Again risk stratified if someone's having mild symptoms or major symptoms how quickly need to get into hospital because If you send them by ambulance by ground You're staying at surface if you decide to fly somebody for decompression sickness They're now at their symptoms could get worse because you're going to pressurize the aircraft And miss repressurize it 5,000 or 7,000 feet. I imagine if they pick you up by helicopter in that situation They just fly low fly low. Yeah, that's what I think so that's the options. I'm good. So it's where that comes up as well. Yeah, okay That's awesome All right, and we were just talking about computers as you mentioned And kind of the science of the compression and I'm always curious because When I did my research and I dive shearwater the all my computers are shearwater. I don't have any other ones um All of the research that I did was the shearwater Has the industries best the compression algorithm for some reason like everyone Aggries on that or a lot of people agree on that I assume soon to and all these other companies disagree But most divers say shearwater is awesome. Just get that and forget it. It's awesome But how precise are those algorithms though because you know when I put my computer on the computer doesn't know How much I weighed how much you know it doesn't know like I get it that is aerated And it kind of understands how fast I'm breathing and whatever But you could have a person that is half my size breathe kind of the same rates and all of that so when he comes to dive algorithms Do they apply equally to everyone and whether you're you know five five hundred and twenty pounds or six eight three hundred and twenty Pounds whatever it is smoke versus known smoke and uh smoker or diabetic You know when a computer says they usually probably step at 40 feet for whatever minutes of the eco How do they know that you don't need you know double the time or half the time They don't Okay, that's the simple answer hey, so these are these are entirely mathematical models The most common algorithm used out there is called a buelman model build in sixteen it has six it has sixteen theoretical compartments of time What are called half times of loading tissues so fast tissues slow tissues of integration and they model it There's some data from animal models There's some human data from navy divers People getting bent and so forth so they do some things But most of us sitting around this table right now are probably not The size and the fitness and the oxygen capacity and so forth of a navy seal So even if the even the human data out there doesn't apply to 99% of the divers out there So what you have to realize is that these are all Mathematical models so don't push your computer because it doesn't know anything about you it knows a model Like I always wonder how come the computer doesn't like a lot of like we have a A pellet on at home the first thing when you turn it on is how much you wait how how I'll tell you are How come die computers don't ask any of that stuff because it doesn't apply necessarily and different thing It's all it's it's so many factors going into that age Weight hydration status thermal status activity level the faster you you know the fast more you're working the more you're going to On gas the warmer you are the more you're going to on gas the colder you are the less you're going to have to the the Clax example thermals is the way we normally do things is exactly the wrong way to do it We go in the water warm, okay So by being warm we're going to be on gas and a lot of nitrogen by the end of the dive when we're just sitting still Doing a safety stopper sitting still doing deco we've been in the water for an hour now we're cold So when you're cold you're not off-gassing very well So we've gone for exactly what so ideally what you should use go in the water cold Stay cold for your whole dive and then warm up at the end of your dive and that would help you off gas So there's so many factors it's hard to really know i'll bring up one thing about about um The comment you made about sure water and i i love sure water there there might go to computers well While most most computers um work on this builman or builman type model There are other models out there the asuntos And now we use rgbm, which is a reduced gradient bubble model Which is involved with deep stops which we can get into probably another time But it's all just different but again they're just different mathematical models The thing you can also do when you think about these computers they say you can set out a conservancy You know you can how conservative or how aggressive your computer is going to be What that really does is there's a Without getting into the physics what's called an inline? This is what that was going to be my question It's so fun of your mentioning this you just took it out because you have a great explanation About what that lower number in the m value means an upper number What does that mean and what should we set it at and why should we not push that got it? I heard you tell me this Explanation before and i think this is very important And very good this is a very interesting thing Okay, so i'll talk a little bit about that We've got to talk about it all the time So from from some computers you just set how conservative you want to be so how fast you want to go to the water And the more conservative you set it the more conservative you're being and they say for it's going to be But it will shorten your dive from an OD compressed standpoint or it will lengthen your decompression on a decompression What that's a decision you have to make With the sure water computers there's what's called this inline which is as you are it is easier to do it with a chalkboard Which is hard on a radio show but as you are ascending And your tissues are off gassing if you maintain a normal centrate of 30 feet per minute which is what we're all taught And you can come straight to the surface without ever crossing over this M value that's a no decompression dive If at any point at 30 feet per minute coming up you would cross over that that's going to increase your risk of bubbling And that's a quote decompression dive Okay, and you have to stop before crossing the line Off gas over time and then move up a little shallower and then off gas over time and move up over shaw That's how you get out of the wall that's how decompression works The sure water computers have what are called gradient factors and it comes set now I think at 3070 or something like that used to be 3085 and now it's 3070 What does that mean? Well that that basically means how close are you willing to get to the inline? Okay, like how close are you willing to gamble that you're not going to get bent by being aggressively getting out of the water So the first number the 30 is kind of when you would hit your first decompression stop Okay, and the last number is kind of how long you're going to stay at that shallow stop So for most of us for recreational divers especially the first number means nothing really Because you're not going to decompression anyway The second number the the top number you want that to be a relatively low number like 70 or Even lower 70 used to be 85 now stand to 70 that just means you can be in the water long You have a longer safety stop Or you're going to have a shorter no decompression dive because you're just trying to be conservative That's where people get bent the most is that shallow so it's going to let you out of the water once your tissues get to be Well, once you are at 70% of that Amline if you will once you get down to 70% or less it will then let you out of the water for understanding it in simple terms Simple terms would be that if you think of the slope of a line And you make that slope shallower so it's it gets that line gets longer If you're trying to get to a given point let's say to the right I'm trying to describe this little radio and you've got a 45 degrees slope line aiming at that right And when you get to the vertical line of the right you can get out of the water Okay, if you decrease the slope of that line is going to take you longer to get to that right side So that's what you're doing state you're staying you're staying shallow longer to be extra safe So don't push those now, okay We know of instances like not going to discuss it on the show take too long people have pushed them They've tried to get out quicker it's happened Even recently had one of the inner spaces I was at and the guy just yeah, he got out quicker and he stayed out and he went home We did with the reconstruction chamber and then did do it in more diving and you know what it's amazing It's not that big of a difference. This is the other point I want to bring out when you push it versus not pushing it You're really not out you're talking about a few minutes of difference To save your life. It's not silly dog. It's like oh, okay. I you got out three minutes earlier than me and now you're bad So three more minutes of my life underwater, which I want to be at anyway exactly So it's just no reason to push it And and I We mentioned this on one of our episodes for people to do their safety stuff And then they bolt to the surface right? Yeah, yeah, it's a worse thing to do they think it's over at that point Yeah, we did all say to yourself is over just go by the way I want to mention before I forget I wanted to give a shout out to Richard and Michelle Morton a dive tronics They are the authorized USA service center for sheer water. Yeah, absolutely the best sir customer service in the industry credible We're not sponsored by sheer water. We welcome the sponsorship people they want to I mean I've I wonder why I have five of them Exactly, we're not sponsored by sheer water to say this we absolutely love them We love dive tronics too. So shout out to them. They listen to the show. Yeah, they're love them Yeah dive tronics is awesome. They took over the customer service a few years ago for for sheer water Which has always been stay-at-the-art best in the industry Again, you're talking about you know people do things that actually dive Bruce Partridge Good friend Bruce someone Partridge you own sheer water He was a tech diver and he basically said the computers out there aren't what I need I need something better than that So he was an engineer and just he made sure water computers and that's awesome Yeah, and the key with you're saying about the being number one all that kind of stuff about the algorithms and Modering area and so forth the main issue with the sheer water computer. They all use the same Models in the fuel and model to say but the sheer water computer is just so intuitive It's kind of like using an iPhone you know, so it's uh It's very very intuitive. I've never read a manual on a sheer water. I mean, you get there It's just so intuitive. It's very very easy. That's that's their main selling point. They've got a computer. There's rock solid great computer never fails With a very good model Decompression model that you can adjust to be more conservative if you want to and it's so intuitive you can figure it out You know, it's incredibly easy. There's another computer on the market which I will not or was on the market that I won't mention But I remember re-brother training with that and to calibrate that okay, which you've done in your sheer water now It takes like three three button pushes and you're done Yeah, there were 16 steps. I could not memorize them. I had to have them written down in a card and laminated Just to be able to tell the computer that this is a hundred percent oxygen So the difference between that generation of computer and the sheer water is unbelievable Yeah, and I remember going to going to college for computer engineering One of our professors at college said that the holy grail of designing software systems is to make your users feel like they can do anything with it And he often use Microsoft software as examples like if you think about Microsoft PowerPoint You never read a manual about PowerPoint you feel like you can do any like I can I can I am bet a video my prestigious I can figure out I'm gonna go and I'm gonna figure out I bet I can do it That's the same feeling I get with sheer waters like can I put whatever gas mix in this thing? I don't know. I've never done it, but I bet I can figure it out. So anyway You're exactly right big fans. All right question number seven You dog are an advisor for Dan the divers alert network. You mentioned that earlier I wanted to know what are the most common health issues that are reported to Dan right? I mean in terms of Die of accidents and the people needing medical help we talked about people getting you know perhaps air lifted to a Recompression chamber things like that I mean, I have to assume that when you think about dive actions the most common reason is Diverse negligence somebody run out of air without checking their air things like that. It's is the most common thing but outside of The diver's negligence and not paying attention. What are the most common reasons of why dive accidents happen? Okay, well Just a couple aspects of probably the number one phone call that Dan gets is probably sunburn Okay, or something like that sunburn or an in an invitation. They stomach at stung somebody bus stops Get some coral and it got a rash. It's not going away Or an ear issue. So by far The vast majority of their phone calls are fairly benign things But people have adequate you know has reasonable questions about Sunburns ear issues Scrapes bite stings and so forth. So there's all there's all of those things um On top of that the other call they tend to get not from an accident standpoint, but it's going to be I have X disease or I am taking Y medication Can I dive so that's that's by far the most common thing Uh, and a lot of that is because As a physician, I can tell you there's absolutely no training in dive medicine hyperbureg medicine in medical school Okay, the only way you're going to get this is specialized training after we have it zero So experience so what will happen if you go to a physician is we are all trained you know above all do no harm So if someone comes to me with a question, can I do such and such some activity that I that I personally think sounds dangerous With this illness or with this medication my gut response is going to be to say no because I want to make sure you're not putting yourself in harm's way So it takes them understating so for that reason Dan gets a lots of questions And to answer that real quickly the main thing with the medications is the medicines most all have never been tested in a hyperbureg environment like underwater But usually it's not the medicine. It's why someone's taking the medicine. You know, so it's this can I dive um You know on tegrotol okay, well tegrotol is anti seizure medicine So why are you taking tegrotol? Well, I have seizures. Well, the reason not to dive is the seizures not the tegrotol It's the same guy thinks it's more in many more the those things When you take those things out of the equation Then yes a lot of it will be um I think I'm bent. I think my body is bent Whatever where's the closest recompression chamber and that's that's the main phone calls that they that they field That's awesome and and I'm glad you brought up the whole Questioning about can I dive with this Meta or under this medicine or with this ailment or whatever because when you sign up for training and even in some dive trim They make you feel that humongous medical questionnaire right that you have to do a thousand times in your dive career And it has like 200 conditions in it right and you have to answer each one of them You can't you cannot just say like no, I don't have any of this stuff. You have to say one by one No, no, no, no, I don't have this problem. No, I don't have it And if you say yes on one of them you need a doctor's notice or whatever Certificate telling you know from a doctor like I know that this person has Hard disease whatever, but I think that they're healthy enough to go diving So the question is when you look at the humongous list of conditions Do we really need to ask like so many questions to know if someone is able to just go get their open water certification? Like I get it. I understand that lawyers can force some of that stuff on the dive agencies But how much of that and those questions are lawyer driven versus an actual doctor or medical driven Questions right what kind of information will that application convey that could make you change something in your training perhaps or You know How you monitor students right one they're doing training. How do you keep your eyes on them? Like as a doctor will you refuse training? You know Someone or diving with someone who said no on all conditions, but maybe you look at him and you're like Maybe this guy didn't tell it because nobody like once you say no and you sign your name like no one Ask anything or like or if they have a doctor's note, but you you look at the note and you're like I don't know if I trust this one Would you still say no even though they have a doctor's note to be able to There's yeah, that's yeah a lot of information on that so first off the current dive medical has been around for a very very long time Don't quote me on the numbers, but probably 20 years or something a lot of 30 years. Yeah, there is a new one that is currently being evaluated um Undersea hyperbureg medical society And some other agencies kind of come together and try to make this a better form for exactly the reason you're talking about It is not out yet. It's being circulated among the dive agencies now for final approval And it should be coming out and it will be a much better form It's going to have a couple of Handful of questions at the very beginning if those are all negative you're good to go and then if one of those are positive Then it triggers more extensive questions and that we could trigger a dive medical and more importantly like I mentioned most physicians Don't have any dive medical training that form is also going to have a lot of information about why that particular condition Is on the form so that they could uh that physician was like oh Oh, you're worried about such and such well. Yeah, this person could have a problem with that So I'll say no or yeah, I understand what you're saying But for this individual person's condition. No, that's not really an issue So yeah, they can dive so they're gonna try and make it a much better form Yes, it's being fed by a lot of legal issues Everything has to go through lawyers as you can imagine But really what you're trying to accomplish for that form is not being a pain in the neck But is what kind of things will get someone in trouble underwater? Okay, so what kind of things get you in trouble underwater? Well, if you are diving you're going under compression you're going under pressure You've got to worry about boils law right so things volumes gonna shrink So airspace issues if you've got asthma if you've had spontaneous pneumothorax uh, lung you know claps lungs Those kind of things can potentially be Potentially be a problem because if you were to have let's say for arguments Take you have very bad asthma and all the sudden while under pressure You have your airways close off. You've got gas trap distal to that when you ascend That's gonna burst cause air gas embolism so forth and so on so those kind of things come into play um other things would be um physical exertion so if there's reasons you can't physically exert yourself enough underwater for swimming if you were walking um or playing tennis and had a problem you would stop okay and the water you can't always stop okay Right, uh if there's some orthopedic issues where you're worried about someone carrying the weight of tanks and because of compression fractures in their back or whatever that may be an issue The other one the most important one is what's the like that if someone losing consciousness? Okay, if people lose consciousness underwater they will usually drown Okay, so if someone has a seizure disorder, okay, they can play golf okay They can play tennis if they happen to have a seizure while playing those activities That's a problem, but it's not gonna be like to be a life threatening problem if they're to have that underwater They'll probably drown I was sorry to interrupt I was just listening to this episode on the drive here about Val Kilmer Just like a thing about his life Val Kilmer's brother drowned in a hot tub because he had a seizure in drown He was just in a hot tub had a seizure in drown like that's pretty bad If you do that at 60 feet 80 feet you're I mean you're done right so the main things we want to screen for are Airspace diseases that would be in problems because of pressure Something that could potentially cause loss of conscious like cardiac issues like seizure issues And then other things like workload that's why we do the swim test on stuff could be able to do an adequate workload For diving And then other things like can they carry physically carry the tanks and what do they need to do? So that's that's what we're screening for And hopefully the new form will help with that quite a bit make it much more streamlined both for the The for all three for the dive student for the dive instructors and and dive shop owners And for the physician that gets referred hopefully all those people have a better understanding as to Why the form is what it is and hopefully making much smoother process for everybody All right, are there any times where you Well, how would you react if somebody says knowing everything and then you right? Yeah The other problem is one the problems the one the reasons we did the Dan did a thing on a symposium on diving with diabetes and diving especially is because People know the answer they if you say you can't dive with diabetes Let's take for as an example and someone has diabetes. They just write no Right, they just say oh, I don't have that and they lie and they lie and they dive okay Well, you could do that but the problem is what we'd rather accomplish as a medical community is say If you have diabetes there are a small number of people who probably shouldn't dive But there's a large group of people that probably can dive if they do it safely So here's how to do it safely Whereas if it's just gonna be a yes or no and they say no, they're not gonna know the proper way to do it safely So what we want to do is Not make it so cumbersome that people know if they put a yes, they're not gonna be able to dive and they're gonna lie because that's human nature Okay, we want to make sure that if they have a yes That first of all if they can't dive they can't but that's usually a small portion of people But we don't make sure we show them how they can do it safely So that's kind of where those kind of things come into play now If I if someone checks no one everything Cardiac wise and I see a scar on their chest from their median starting from their bypass or valve replacement You know and I hear their airdic valve clicking Then yeah, I may say look let's let's be a little more honest. We'll just have a discussion You know about things so of course it's easier for me as a dive instructor because I'm also a diving medicine physician So what I tell people is here's the form, you know, let me know if you're gonna say yes or anything We'll discuss kind of what that means or doesn't mean and so forth and so on Would you most people can't do that would you override another doctor's note if if you disagree with it like if you if the patient comes with a node and says yes, I do have this condition, but my doctor said it's cool Potentially it depends again. I have to and I'll just do this like for my physician My job is to train that person safely so they can safely dive if in my mind Said I think it's not safe for them to dive. That's my opinion Yeah, and I don't want to put myself in jeopardy have to save them because I'm concerned Then I can always refuse to train them That may get them mad at me and that's okay. I'm looking out for best for them medically. I could say I know your doctor said this I'm sorry, but I don't feel comfortable with that decision because of My rationale and I would recommend you either talk to your physician some more talk to a different physician Or get a different instructor, but I'm not personally comfortable with taking you underwater and putting you in me in jeopardy Right, they shouldn't say no like it people need to understand that Dive shops and dive charters and all those they want to take you diving You know for them to say you can dive It requires like an overwhelming amount of evidence that okay We don't want to have a risk and we don't think you should Legitimately go diving they're not looking for any excuse to tell you no no they're actually looking to take you diving That's how they're living exactly but at the same time they realize they're also not medical professionals Then they don't they say what we have to the form says if there's a yes You have to see a doctor. We can't change that you said yes. You need to see a doctor That's not our decision. That's the RSTC's you know decision, so we're not the bad guy here We're just trying to look out what's safe for you. Yeah for dive instructors We've had issues where the doctors will qualify it. They'll put conditions that gets tricky Right, so they'll say yes, you can dive if you don't do this or if you do that So as a dive professional, that's a problem for us, right? We have to pause We've had to call Dan before on issues like that typically if We see any condition other than yes, it's fine absolutely yes. Yeah, we don't take them Right the classic example of one that you can tell the doctor is just trying to be cautious But doesn't know what they're talking about is they'll say oh well somebody has asthma so they can dive But don't take them deeper than 30 feet well Obviously, we just talked about the change from zero to feet to 30 feet is much bigger than the volume change between 30 feet and 100 feet So they're safe or change going from 100 feet to 30 feet then they are from going 30 feet to the surface That's clearly not the right answer That's interesting. All right, so we're getting cut. We're getting here close to the end my question number nine is You know, I'm trying to understand like the the whole thing about oxygen right and I by diving close Circuit re-breathers we get to breathe a hundred percent all to whenever we need to especially as we're getting Closes surface and you know, I've never done drugs or smoke cigarettes or anything like that But breathing a hundred percent all to other surfaces awesome like it feels great You feel warmer ages. It's just better But then if you go a hundred feet deep in plus it becomes a full-on poison that you can have a you know seizure and die from from breathing. Oh, why is that what and apparently the higher you go the better It is right. That's why people climb average and stuff with oxygen because it's awesome the higher you go the better it is How come oxygen is toxic at depth We don't know exactly why it's toxic, but we know there is that it's what what actually happens is Your body doesn't really care what fraction of oxygen you're breathing What your body cares about is the partial pressure of oxygen so it's the fraction versus multiplied by the absolute Atmissures well most of us walk around at sea level right so those those numbers are the same So your fraction of oxygen and your partial pressure of oxygen are the same is 21 percent so it's 0.21 First off, let me back up and to say if you feel brother breathing oxygen at sea level it's placebo Okay, it doesn't do anything because your oxygen love your oxygen saturation curve in your body You have a sigmoid shaped curve and the difference between Being 94 percent and 99 percent is a very small very flat portion of the curves. It doesn't make any difference So that doesn't that's placebo But as you go let's take the to take altitude first if you go to altitude You're no longer at one atmosphere right if you go to top of Everest you're at the equivalent of point three It's like a third of an atmosphere by going 30,000 feet So if you're at a third of an atmosphere and you're breathing air 21 percent your partial pressure of oxygen is a third of 21 percent or is the equivalent of breathing 7 percent oxygen at the surface How well do you think you'll do here at sea level breathing 7 percent oxygen not very well right? That's why oxygen helps at altitude And that's why they said if so you take a helicopter and they drop you off at the summit of Everest you'll die Five minutes because you don't you don't time to cool right? That's why people go to base camp and in equivalents over so that's that's the that's the elevation So it definitely can help that so if people are skiing let's say for you there's somewhere high And they're skiing at 10,000 12,000 feet and they feel like crap and they want to go on oxygen Yeah, they make a little bit of difference because again, you're not at sea level anymore So your your atmospheres for that partial pressure are less than one so your your functioning is if you're breathing not 21 percent but more like pick a number of 15 16 17 18 percent So less than that and what often happens is your body tries to compensate for that by by breathing rapidly You're breathing deeply deeply and then you blow off too much carbon dioxide and when you do that You get what's called a respiratory alkalosis base You become your acid-based status gets mixed up and then you start feeling bad That's kind of the whole altitude sickness when people get to go to veil for the first day And they go to the top of the mountain and feel bad. So that's that's going up on the way down So when we're scuba diving same sort of thing happens and our body does very well From a partial pressure standpoint from about point one six of oxygen, which would be 16 percent of the surface To 1.6 beyond 1.6 which would be if you're at 200 feet would be basically breathing air, okay? So air deep than 200 feet. Get you above 1.6 Or around that kind of number so 1.44 But anyway, regardless The idea is then you start getting the neurologic problems and we know with high partial pressures of oxygen You get neurologic issues and the number one is convulsions or seizures. So again If you were to have that underwater, that's fatal If we put people in a recompression chamber they will frequently put them at two point something two point eight At the series of oxygen so you go well crap don't people seize in a recompression chamber Yeah, they do occasionally But they're not going to drown they're they're in an air environment. They're not going to drown So how much you want to push those things is how that happens? So that's why for people who are nitrox certified Out there on the they're listening we have a maximum partial pressure of oxygen of 1.4 And that's the maximum you can do nitrox diving now is 1.4 is that a A cut point like it you have no risk at 1.39 and everybody ceases at 1.41 Absolutely not we're just drawing a line in the sand the lower the partial pressure of oxygen The less like the yard have an oxygen toxicity seizure But also the for nitrox diving the lower that partial pressure the more nitrogen you're loading so the more Decompression you have or shorter no decompression limit you have So all of these things are a tradeoff and it's a teeter totter where you've got oxygen toxicity on one side And you've got no decompression limits or decompression time on the other side of the teeter totter And you just flip them back and forth find the sweet spot for you. That's kind of how all that works I'm talking about the teeter totter And this is just a personal question. Where do you keep your levels when you're Rebrea they're diving the 1.2s or 1.3s or where are you normally exactly? The way to look at that is Again, I don't know who the people listening to are you know the show are but just you know if you keep yourself at 1.3 For toxicity purposes you can do a single three hour dive Okay, if you keep yourself at 1.2 you can do a little bit longer than a three hour dive and you can get four hours of diving during the day so for the usual Recreational or minimal deco kind of diving Time-wise I usually go about 1.2 now you hear about people that do these 16 18 hour dives right Some long cave thing or whatever if you think about that there's no way in the world they can keep their p.o. 2 1.2 Right, I mean they would they would have oxygen toxicity So they may be diving 0.5 0.6 something low wow, which basically means There are oxygen toxicity in the lobe. What do you think that does their decompression? It jacks it way up. So again, you got to find the sweet spot for the individual dive of weighing oxygen toxicity risk versus decompression So you adjust yours your personal one you adjust the base on the dive you're doing Somewhat I'll be honest with you. I don't do those long dives Okay, the longest dive I don't want to be in the water more than three hours or so So for most two and a half three hour dives I keep it 1.2 All right, so in the 1.2 range 1.2 0 to 1.2 From training standpoint the maximum recommended p.o. 2 is is 1.3 Now if you're doing a dive at blue hair and bridge today and it's 20 feet deep But we're on our re-breathers because we all brought them. Yeah, you don't need to keep yourself What's your decompression risk breathing air at 20 feet basically zero? Right? So you could theoretically be diving a point to 1. Okay, so I'll probably today I'll probably dive point seven. I'll probably keep it kind of point seven You know something like that. So you have to play on either side Awesome, and we have arrived through our final question. This is more of a thing that I've noticed like especially like I I don't know if Woody has noticed this because he's always driving with 30 layers and an astronaut suit As well, but for me I even though I'm dry suit certified I have a dry suit. I love it a fourth element that I love But I personally think it's too bulky. It's too much work to Put it on carrier with you whatever you travel, you know, put it on it's too much work So I typically like to do wetsuit even though I have a dry suit and I love it But one of the things that I noticed is that I feel like I need to pee often like all the time I don't know why so why do people have to pee Way more often when they're diving is it the water around you? Is it the temperatures of both like what's going on? It's both First off if you're cold Okay, your body wants to keep the vital organs alive. Okay, so it wants it'll sacrifice the extremities To maintain the core So you get some vasoconstriction of the blood vessels which will shift water shift to see if bloodstream is of within into the central circulation That that volume is then filtered by your kidneys because all the blood's going through the kidneys and that's going to generate more urine Same thing happens just for going in the water even in your dry suit Just being immersed in water Triggers what's called the diving reflexes for our mammalian reflex like dolphins and whales and so forth Our heart rate slows and some other things happen Well, again, what happens classical just for going underwater period is you'll shift about 700 cc So about a pipe and a half Of fluid from the periphery from the arms and legs into the central circulation Which then gets filtered by the kidneys and generates more urine. So it's very very common So yeah, that's why you have to urinate from diving when you don't have to do it when you're doing something else some other activity Yeah, that's important because for lots of reasons for self-peeing standpoint You know as I'm sure you know the old saying that there's two types of divers of the pee and the wetsuits and those that lie about it Yeah But if you're not peeing that's a problem because you're probably very dehydrated and dehydration but you're risk for decompression sickness So from a diving standpoint you want your urine to be clear and copious Okay, if it's yellow and not very common then you're much you're very dehydrated. So that's that's going to what happens It's the combination of shifting your way pro peeing in the suit Oh, I'm different pro peeing in suits I have a very very much in favor of peeing in your suit I don't lie about that I'm peeing in suit as to go Yeah Although some of us have peeing in our dry suit I've never done that recently my action you know the end of a dive that was freezing freezing cold Got a little leak it in okay. I peed in my cool. I suit so we are I want the world to know that I just recently peed in my dry suit Okay, I had to get that out that's real better getting that out by the way You feel better. That's all I contributed to this you know For people who listen to me to be this quiet people listen to show good what is going on with Woody? I fell like you would have eaten her up I'm gonna continue to help I thought you were gonna at least in one of the questions be like actually dog I don't think that's how it works All right, so uh, thank you dog for answering I guess my top 10 dive questions I do have a bonus question I guess and this one is just for fun And I was talking to my wife about this last week You know she's always yelling at me because I don't drink enough water. I just don't get thirsty and She follows this idea of you are supposed to drink eight I ate ounce glasses of water every day like no matter what she likes to drink eight eight ounce glasses of water That's something that she's been doing for years and she wants to push me to do it I can't force myself to do it. I don't know why it's like it's too much water But then at the same time watching a ballgame I can drink 12 beers so Why why is that a thing? I don't understand Uh, yeah drinking water is good. I don't drink that much water either But uh, but drinking water is very good as far as the difference between that and your alcohol There's probably a couple things for us all the alcohol tastes better than water So you're probably a little bit more likely to drink a beer than you are to drink ounce of water, but secondly all kidding aside alcohol is a diuretic So it will cause you to urinate you lose your drink a lot you pee a lot Yeah, and so you actually will get rid of a lot of that volume more than you would just drinking water every day So it's healthier to drink beer. I wouldn't say that But uh, but it would it would it is a diuretic it will make you pee more and will make you more dehydrated Which is be making more likely to be able to drink more of it I think but I think mainly it's probably because you enjoyed drinking beer watching a ball game And you don't like taking a good eight ounce glass of bland water drinking it for the heck of it I know it's lame Would he any final thoughts or dog as well as we wrap up the episode? I mean just thanks dog That's so great. This is really important information And that's kind of our goal right to disseminate in the end if you think about all of these shows We're really trying to just make people safer divers That's what almost the whole thing of dive of dive talks about we love diving So we love to talk about diving But if you notice like all the shows ultimately come back and narrow down to the topic of even we're talking about ecology safety Like that's what today's show is all about so take these things for real It's a serious amount of information we just covered because we have a great great thing that we do We go visit you know underneath the ocean and alien species and all that But we're not made to be underwater are we right look at us. We're so fragile So we have to do all these things that yes and no question on the medical for example So dive safe that's really what the theme of this show is today Yeah, any final words? No, thank you for having me. I appreciate hope this was helpful If anyone has any questions for you I know they can reach us always at info a dive talk media.com or go to dive talk media.com for all of our episodes What if they have any questions for you? Where can they find you? I know that you mentioned that you get some Private messages and stuff through the scuba boards or what's the best way if they listen to this episode? You know actually now that I think about it. Let me ask this question. What's the best way to reach you? The best way to reach me is just through an email Which my email would be is D as in my first name of Doug G my middle initial is Glenn So DG ever soul at eb e r s o l e at gmail.com perfect Thank you so much Doug Woody see you next week and a couple weeks