Fatigue and nitrox

[gcbryan]

Before I took up diving I used to do a lot of backpacking. My pack usually weighed about 35 pounds. After a day of mountain climbing I was exhausted. I began diving and suddenly found myself carrying 80-120 pounds of gear on my back, hiking in a drysuit and entering surf from a rocky beach. After spending 60-120+ minutes in 50F water +- a few degrees, I would climb back out of the water, up the hill and plop down on the tailgate of my truck. I feel the same after a dive no matter what gasses I use.

I agree with this as well but for me it's a different feeling. With one I'm tired as my muscles are sore...for good reason but if you feel like sleeping for 12 hours after two recreational dives with easy shore entry that's a different matter. Also, if slowing the ascent and spending more time shallow doesn't clear things up then you probably are just tired from all the other factors mentioned.

It's two different problems/situations in my experience. Maybe all of your entries are tiring (Calif diving) and maybe your ascents are already slow and you already spend a bit more time shallow then needed so maybe you've always avoided this problem in the first place. I don't have this problem anymore either.

 

[schaffld]

Yes, I find this to be a fascinating subject also.

I appreciate Thalassamania's reasonable and rational explanation and observations. My perspective is from a recreational diver's point of view and my bias is more towards the placebo effect for this group of divers. However, I will concede that the extensive multi-dives over mult-days scenario is a completely different kettle of fish and the benefits of Nitrox are definitely worth further investigation especially if there is a tangible improvement in safety for commercial, military, and scientific divers.

Much of this thread has been a debate about the mechanism of how Nitrox can lessen post-dive fatigue without actually establishing that there is any such effect in the first place. Again, my position is with respect to recreational divers. I believe there are just too many other variables to consider before we can suggest that diving with Nitrox will lessen post-dive fatigue.

Some well designed investigations into any cause/effect relationship and the possible mechanisms of such relationships would be fascinating and bring us out of the 1800's, as a previous post by Valery remarked.

My approach to answering questions about Nitrox focuses on what we do know. It extends NDL, and that's incentive enough for me to encourage recreational divers to learn about its benefits and risks. I think it is irresponsible for someone to tout Nitrox as a "feel good" gas whether or not their experience leads them to believe that they benefit in this way.

 

[Bubbletrubble]

I am not a medical doctor! I fix sick Networks. However, I learned something from a Dan presenter a few years ago.

Most recreational divers suffer from Type II DCS (neurological). Marked fatigue is also a symptom of cub-clinical DCS as well as more advanced stages of DCS.

He then went to point out that the half times for blood and neural fluids are pretty similar (3-5 minutes). It is my humble belief that anything to reduce N2 during and after the dive will also reduce fatigue. However, I believe that the rate of ascent has more to do with this than anything else.

@NetDoc: Did the DAN presenter explain what he meant by "neural fluids"? Was he referring to cerebrospinal fluid (CSF)? If so, did he elaborate on how nitrogen load in CSF might be altering neurological function?

The reason I'm interested is that patients afflicted with multiple sclerosis (MS) often complain of severe fatigue, which can lead some to sleep for unusually long periods of time (12 hrs.). Now I'm not saying that the pathologic mechanism in MS is the same as in DCS-related fatigue, but it wouldn't be a huge stretch to imagine heightened nitrogen load leading to inflammation which then interferes with neurological transmission. Just a thought...

 

[Valery]

Well thank you all for your inputs, it really helped me understand a little better what’s happening to me and what to do to try to correct this problem.

I wanted to fix this “tired thing” before going deeper next season.

PFO = Patent Foramen Ovale

A hole in the wall separating the left and right atria in your heart. It's necessary during our fetal development but usually closes shortly after we are born.
…
that's a PFO in 75 words or less...

Thanks God I’ve no PFO or blood sugar problem.

@idocsteve:…

Valéry's significant post-dive fatigue is very likely related to decompressing too quickly. An extended safety stop would probably help with that. Another strategy would be for her to limit her nitrogen loading in the first place.

No problem here, I really think that my deco profile could fix this, except that before you guys start asking for my phone number (women are as rare as dolphin in the dive world), Valéry is a He (not helium)

Fascinating subject.

I have always noted that fatigue was a primary indicator for my personal diving that I was pre-DCS and approaching Type I. I figured that it was reasonably believed, and I'm …

At Duke, testing negative for a PFO was foremost on the requirements for entry.

I agree with most of your comments:
I am certain that gas loading (nitrogen or other) into the body is what is making me tired (tired like you described as before flu or hitted by a truck), there is certainly other factor such as a better breathing technique, but I’ll deal with 1 factor at a time.
I’m surely going home with to much nitrogen in my body. I’ll try more conservatism and adding deep stops if my ascent to first stop is too hard.
Then if my problem is solved with this change in deco profile, I will add 50% or 100% oxygen in my deco.

I’ll keep you informed of what’s happening but be patient it will take time as we are off season, I’m only diving on Sundays if the weather allows for.

 

[Bubbletrubble]

No problem here, I really think that my deco profile could fix this, except that before you guys start asking for my phone number (women are as rare as dolphin in the dive world), Valéry is a He (not helium)

Dude, I'm so sorry for that. :hiding:

 

[The Chairman]

@NetDoc: Did the DAN presenter explain what he meant by "neural fluids"? Was he referring to cerebrospinal fluid (CSF)? If so, did he elaborate on how nitrogen load in CSF might be altering neurological function

I don't recall him delineating between spinal and cerebral fluids. I would imagine that they are close. Dr Deco can fill us in on this.

 

[Bubbletrubble]

I don't recall him delineating between spinal and cerebral fluids. I would imagine that they are close.

Hmmm. That's interesting. I wouldn't expect that to be the case. Furthermore, I'd think measuring that would prove to be very problematic.

 

[Kern]

Val, I'm a little confused by some of the things you've said. Could you tell us a bit more about the dives you are doing that cause you to fell tired. Things like NDL or deco, depth, bottom time, run time, back gas, deco gases & are you running Bhullman gradient factors or VPM_B & at what conservatism on your X1.

 

[miketsp]

It's simple, just breath pure o2 for 20 minutes at the end of the day and you'll feel great!
..snip..

I remember a few years back, here in Sao Paulo, there was a craze in quite a few night-clubs of inhaling pure O2 as a stimulant. You paid an exorbitant price and got a mask to inhale O2 for 5 or 10 minutes.
The craze soon died out once people realized it was pure hype.

 

[Valery]

Val, I'm a little confused by some of the things you've said. Could you tell us a bit more about the dives you are doing that cause you to fell tired. Things like NDL or deco, depth, bottom time, run time, back gas, deco gases & are you running Bhullman gradient factors or VPM_B & at what conservatism on your X1.

Well let's say that those dives are between 30 and 40m (a small part of the dive is at this depth), reef, swimming 90% of the time and the speed is a little more than normal, duration between 30 and 40 mins.

Not to much deco 15mins (or less) rarely 20mins or more. Gas is Air even for deco. We dive at a club and we all have different level so we all dive with air to be at the same time on the boat, but this should be fixed as next season there will be more advanced divers.

If I don’t succeed in fixing the problem, I'll post several profile dives as soon as possible.


My X1 is new and I haven’t logged any thing interesting on it yet. The problem started before I bought it, I use to dive and follow my instructor deco who has a VRX set to 0.