Capt Jim Wyatt
Hanging at the 10 Foot Stop
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Sold On Nitrox
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kaylee_ann
crazy diver
Wait, so post-dive exhaustion isn’t normal? I thought most divers had it. I never really was one for safety stops, but was going to start them mainly to practice holding neutral buoyancy for deco stops. Guess this is a better reason.
For now, my dives are gas-consumption limited rather than NDL (my perfectionist anxiety goes through the roof!). But you don’t get narced as early, or take on as much N2, which are the reasons I’m interested right now.NitrOx is a great tool to keep the N2 down, even while extending your dives a bit. The tendency is to go to bigger tanks, since the amount of gas you carry becomes more of a limiting factor. Remember that you don't HAVE to ride you NDL. The more margin you leave, the better off you'll be, especially with multiple dives over multiple days. It's a big ocean. You're not going to see it all in one dive, so don't try!
Yeah…gonna have to break up the dives
kaylee_ann
crazy diver
It’s odd, because if I’m staying active, I won’t notice the tiredness because my adrenaline is up. For example, if I’m hanging out with dive buddies or other friends. When driving, it gets a little rough, but not horrible as I’ve trained myself to not be drowsy in a car (long solo drives). When I’m not busy anymore is when I crash. I thought it happened to everyone?
You'll have to let me know after we finish with our dives
kaylee_ann
crazy diver
Well, that wouldn’t be the most reliable metric. Remember I’m driving nearly a full day to get there.You'll have to let me know after we finish with our dives
I’ll be tired anyway. But it’ll be cool to see how I feel now since my prior health issues have been resolved, plus nitrox!RobPNW
Contributor
I know this doesn't directly address the OP's post but since some have made comments about heat transfer I'll share some info from an article that I read many years ago. It was back during the jogging craze when people were out running around in cheesy short shorts, knee high socks and headbands.
A study was done to try and determine the best cardio exercise for weight loss and they picked jogging, cycling and swimming as the candidates. The preconceived consensus was that swimming would be the winner because of the whole body nature of the exercise. What in fact happened, however, is joggers lost the most weight, cyclers lost the next most, and swimmers GAINED weight.
Everyone was shocked by the results but after some physiological research, it made more sense and was quite interesting. Since there's a significantly higher heat transfer rate in water versus air, the swimmer's temperature was dropping during exercise. That triggered a response for the hypothalamus gland to kick in because it regulates body temperature. Makes sense so far but what does that have to do with being tired?
Well, the hypothalamus also plays a role in sleep patterns and feeding patterns. I'm no doctor so I don't know how it works, just relaying what the article said. So, it seems, when diving, the accelerated heat transfer would stimulate that gland. And the implication is that is a significant reason why many people get finished with a dive and want to do two things - eat and take a nap
So then, what does that have to do with Nitrox? Maybe it has nothing to do with it. But maybe the ever so slightly elevated oxygenation of the blood helps the metabolism keep the diver warmer? Oxygen is needed for the metabolism to burn calories for heat. Maybe there's a tie-in there. Regardless, diving is going to make people sleepy and hungry.
A study was done to try and determine the best cardio exercise for weight loss and they picked jogging, cycling and swimming as the candidates. The preconceived consensus was that swimming would be the winner because of the whole body nature of the exercise. What in fact happened, however, is joggers lost the most weight, cyclers lost the next most, and swimmers GAINED weight.
Everyone was shocked by the results but after some physiological research, it made more sense and was quite interesting. Since there's a significantly higher heat transfer rate in water versus air, the swimmer's temperature was dropping during exercise. That triggered a response for the hypothalamus gland to kick in because it regulates body temperature. Makes sense so far but what does that have to do with being tired?
Well, the hypothalamus also plays a role in sleep patterns and feeding patterns. I'm no doctor so I don't know how it works, just relaying what the article said. So, it seems, when diving, the accelerated heat transfer would stimulate that gland. And the implication is that is a significant reason why many people get finished with a dive and want to do two things - eat and take a nap
So then, what does that have to do with Nitrox? Maybe it has nothing to do with it. But maybe the ever so slightly elevated oxygenation of the blood helps the metabolism keep the diver warmer? Oxygen is needed for the metabolism to burn calories for heat. Maybe there's a tie-in there. Regardless, diving is going to make people sleepy and hungry.
PatW
Contributor
I have used nitrox and air. To me, I do not notice a difference. As far as nitrogen load, I tend to not go anywhere near deco limits. Sometimes it happens but usually not. I do keep track of deco limits and nitros does give me a far larger cushion.
My wife claims that she feels far less fatigue diving on nitrox.
We are both fit. We are both cyclists and ride about three times per week.
As far as the effects of chilling goes, my wife likes far more thermo protection than I do. I used to be able to dive 3 dives at 78 degrees in a skin. My wife would use a 3 mm. As I have aged, I need more thermal protection.
Nirox should not have an effect from increased oxygen - human blood is basically 98-99 % saturated at sea level. Increased oxygen tension will not increase blood O2 content. Oxygen might have some other effect but seemingly not from increased oxygen transport in the blood. The other effect might be from decreased nitrogen loading.
Or it could be a placebo effect. The placebo effect is quite strong so it might be sufficient. Or it could be placebo effect AND something else acting together.
Scientists like to call things like this “poorly understood”. That is scientist taok for ”we don’t have a clue”.
My wife claims that she feels far less fatigue diving on nitrox.
We are both fit. We are both cyclists and ride about three times per week.
As far as the effects of chilling goes, my wife likes far more thermo protection than I do. I used to be able to dive 3 dives at 78 degrees in a skin. My wife would use a 3 mm. As I have aged, I need more thermal protection.
Nirox should not have an effect from increased oxygen - human blood is basically 98-99 % saturated at sea level. Increased oxygen tension will not increase blood O2 content. Oxygen might have some other effect but seemingly not from increased oxygen transport in the blood. The other effect might be from decreased nitrogen loading.
Or it could be a placebo effect. The placebo effect is quite strong so it might be sufficient. Or it could be placebo effect AND something else acting together.
Scientists like to call things like this “poorly understood”. That is scientist taok for ”we don’t have a clue”.
RobPNW
Contributor
The Chairman
Chairman of the Board
Most divers who do a 3 minute or less safety stop, aka safety pauses, get that post dive exhaustion.
Yeppers. Glad to be of service, ma'am.
Yes, you do. O2 is as narcotic as N2. Narcosis can be exacerbated by cold, dark, stress, and unfamiliarity. The only relief is to ascend until it passes.
Exactly.
NitrOx has a number of nicknames, but Geezer Gas is my favorite. If you're over 40, your cells have begun to lose elasticity, which makes it harder to get rid of excess N2. Less in means less to get out. In addition, different tissue types ongass/offgas at different speeds with Neural and Blood tissues having the fastest at @ 5 minutes.
5 minutes.
So, doing a full five-minute safety stop allows fully half of the excess nitrogen to leave your neural systems. But, why not just surface and do it on the hard? Well, once N2 starts to come out of solution (micro-bubbles), it gets increasingly hard to get rid of. N2 is tolerable. N2 as micro-bubbles is bad. The less N2 is in your blood, the less likely it is to produce micro-bubbles. Think of it as surface narcosis in that it dulls your senses.
The best way to clear excess N2 is to go on O2 during your safety stop.
But, you'll have to take extended range to do that.
I thought I found that Nitrox was helpful on days when as a DM I was doing 4-6 checkouts with students. turns out what was really helping is taking more time on the stops and allowing my body to get rid of the nitrogen under pressure. Less stressing from a physiological standpoint.
The less time you spend decompressing under some pressure is more strain on the body.
And yes, at the safety stop you are decompressing because every dive is a decompression dive.
For recreational diving for fun, less the dives were in excess of 80ft or so, I found no real benefit to the extra cost. Mainly because as I got older, I wasn't interested in doing more than 2-3 dives a day.
And the more I dived the slower I swam because it's not a race.
And as Pete said, a 5 minute stop was much better and more enjoyable on those deeper dives.
On top of an ascent that I might spend 10 minutes doing coming up from 15-20 feet just because I wanted to.
Another thing is that if you can avoid it, don't rush to get out of the water and climb the stairs or ladder with all that stuff on. It's why I love sidemount. Especially in lakes and quarries. I don't get out of the water with my cylinders. Clip them off to the drop line, get out with the just the harness.
The less time you spend decompressing under some pressure is more strain on the body.
And yes, at the safety stop you are decompressing because every dive is a decompression dive.
For recreational diving for fun, less the dives were in excess of 80ft or so, I found no real benefit to the extra cost. Mainly because as I got older, I wasn't interested in doing more than 2-3 dives a day.
And the more I dived the slower I swam because it's not a race.
And as Pete said, a 5 minute stop was much better and more enjoyable on those deeper dives.
On top of an ascent that I might spend 10 minutes doing coming up from 15-20 feet just because I wanted to.
Another thing is that if you can avoid it, don't rush to get out of the water and climb the stairs or ladder with all that stuff on. It's why I love sidemount. Especially in lakes and quarries. I don't get out of the water with my cylinders. Clip them off to the drop line, get out with the just the harness.
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