Nitrox extends NDL but does it have other benefits?

[Nirvana]

I hope someone can explain to me why increased oxygen under pressure provides such a wonderful benefit in hyperbaric oxygen therapy but has no benefit when diving.

I am not a physician, but I'll venture an explanation. Breathing a higher ppO2 while diving does give the same healing benefits of O2 in a chamber. However, the partial pressure is lesser, as is duration of exposure than in a chamber, to prevent against an O2 tox event underwater and DCS (assuming it is not pure O2 being breathed). In addition, only relatively healthy people can dive, so those who would benefit the most from O2 exposure are prevented from doing it underwater.

In summation, breathing compressed gases with elevated O2 probably has healing properties, but as it is done to divers, it is to an intensity and to healthy enough people as not to be noticed.

 

[MaxBottomtime]

This study subjected divers to a chamber dive of about 60 feet for 40 minutes and then tested their fatigue levels. As I said, I don't think that is enough of a stressor to be able to tell a difference.

Another test was published in 2008 using 36% and having eleven dives make two repetitive air dives and two repetitive EAN36 dives to eighteen meters in water on separate, nonconsecutive days. The results confirmed the earlier study.
Measurement of Fatigue following 18 msw Open Water Dives Breathing Air or EAN36.

 

[victorzamora]

Here's my anecdotal evidence for those that care:

I dive Jackson Blue a lot. It's easy, I know the area, I know Edd and his shop and his guys, I like it. My usual trip down there is drive down Friday night, dive all day Saturday, and then dive Sunday morning...hoping to leave by 2pm. I've done this several times. Before I started doing deco on O2, my wife would have to drive home on Sunday afternoon.....it's a 7 hour drive, I always took an hour nap sometime on the ride home. Like clockwork. I've done two trips since I've started decoing out on O2 (finally bought an O2 bottle and reg) and both of them have had more/longer dives than the previous trips.....as well as a little less sleep both Friday AND Saturday nights, yet I've been awake on both of the drive back after that. I've got a trip without my wife this weekend, and I'll be doing a safety stop on oxygen before my drive back....just to make sure I stay awake long enough. I've never felt better after a cave dive than my first Sunday afternoon with O2. Purely anecdotal, in no way was it scientific, or repeatable, but statistically close enough for me.

 

[boulderjohn]

Another test was published in 2008 using 36% and having eleven dives make two repetitive air dives and two repetitive EAN36 dives to eighteen meters in water on separate, nonconsecutive days. The results confirmed the earlier study.
Measurement of Fatigue following 18 msw Open Water Dives Breathing Air or EAN36.

Again, my same complaint. I would not feel fatigued enough on dives that short and that shallow to notice a difference. I feel a significant difference doing multiple dives per day over several consecutive days, and I wonder why they don't test that way.

 

[Tigerman]

I feel no difference whatsoever diving air or nitrox. I DO notice a significant difference on my NDLs for consecutive dives though...

Sent fra min GT-I9300 via Tapatalk

 

[rhwestfall]

Again, my same complaint. I would not feel fatigued enough on dives that short and that shallow to notice a difference. I feel a significant difference doing multiple dives per day over several consecutive days, and I wonder why they don't test that way.

Likely too many variables to control to get the test to be "valid". Sleep, hydration, diet, etc. all are postulated to play a role. When you extend the test time, you introduce the possibility of "contamination".

 

[boulderjohn]

Likely too many variables to control to get the test to be "valid". Sleep, hydration, diet, etc. all are postulated to play a role. When you extend the test time, you introduce the possibility of "contamination".

Studies like that are done all the time. Think of all the studies of diet, weight loss, medication, etc. you read about. They have far more variables. I used to do educational research, and that is far less controlled, and it has to be. If you have a big enough sample size, you assume those variables even out. If you have a small sample size, you really can't draw a meaningful conclusion anyway.

I think their is a different reason. It will be tough to get a big enough sample without spending more money than they want to spend. The other studies mentioned are pretty cheap.

 

[Wookie]

I think their is a different reason. It will be tough to get a big enough sample without spending more money than they want to spend. The other studies mentioned are pretty cheap.

Ask any liveaboard. We love that stuff. First 2 days of liveaboard diving on air, second 2 on nicetrox. Or, 2 boats, Spree and Ultimate Getaway or Spree and Fling, all similar boats, all in the same place, do one boat air and one nicetrox. Customers pay for the trip. Researcher only has to come up with protocols.

Really, does it make a difference? That's why no one has done any real research. No one cares.

 

[Scubagolf]

Again, my same complaint. I would not feel fatigued enough on dives that short and that shallow to notice a difference. I feel a significant difference doing multiple dives per day over several consecutive days, and I wonder why they don't test that way.

My diving is almost always 5-6 days of 2 or 3 dives/day. I am 63 and have noticeably less fatigue at the end of the day diving EAN 32 or 36. If it is a placebo effect, it still works.

 

[archiebald]

I am so glad I asked this question and thanks to all for a great set of replies. Skimming through the replies, the pattern that seems to be emerging is this;

If you are diving well within your personal physical limits (either as a result of age or physical fitness or diving quantity) your body has enough energy reserves at the end of the day to make the effects of nitrox on fatigue levels either negligible or non existent.

However if you are diving closer to your personal limits (either by age, fitness or quantity of dives) to the extent that you are draining your energy reserves, then the use of nitrox can have a noticeable effect on reducing fatigue at the end of the day.

This would certainly address the point that some divers report they do and some divers report they don't feel the difference. Not sure if that is really the case but it has a certain logic. And, since I am 52 and my daughter is 15, maybe nitrox will allow me to keep up with her a little better

With regard to the therapeutic use of oxygen rich environments, about 8 years years ago I had a severe ear infection that my local hospital attempted to treat by putting me in a hyperbaric chamber with 100% oxygen at around 1.5 bar pressure. I had several two hour sessions over a few days. They warned me it may not work as the results of the treatment vary by patient. However, they still keep it as an option for use in various treatments. As already stated by others, the oxygen rich environment speeds up the body's natural healing functions which in certain injuries and illnesses can help prevent permanent tissue damage.