Any Advantages in Nitrox for older divers?

[Ardy]

Hi Dr Deco - I've been diving for 35 years and although I have read a fair amount about Nitrox I never felt the need to go there.

As I am 62 now I was wondering if there are any advantages or disadvantages in going Nitrox for older divers?

 

[cutlass]

I'll take a shot and say "It depends on what you're really asking". The benefits and limits of enriched oxygen in diving are quite standardized. Within limits, it could lower your DCS risk and could raise your allowable bottom time. AFAIK, age is not so much a factor as general health.

Beyond that, I sense that this question may be motivated by testimonial evidence about the benefits of supplemental oxygen, something hyped by fad "oxygen bars" where, instead of booze, people belly-up for an oxygen hit. (The doses vary but they seem to be roughly equivalent to common therapy mixtures delivered with nasal cannula/prongs. These levels appear to be about the same as nitrox mixes at sea level.) Touted benefits are increase in alertness and energy, reduction of headaches, cramps, miscellaneous aches/pains, and general relaxation. One also hears about such things as the benefits of hyperbaric oxygen-rich treatment for wound healing, especially burns and infections. All seemingly goodness. But sorry, AFAIK there are no well-controlled studies about such benefits applying to healthy people; certainly not in the long term. Even the supplemental oxygen commonly seen being sucked up by athletes has its benefits disputed; the exception is if the athlete is unacclimatized to a high-altitude venue. OTOH to be fair, short term occasional low flow oxygen supplementation has not been demonstrated to be particularly dangerous to a healthy person. (People with certain heart or lung problems or undergoing certain chemotherapies must have their supplemental oxygen carefully prescribed and monitored.) In the end, the benefits of nitrox diving is just what is taught.

 

[Dr Deco]

Hello Ardy :


Dive tables are calculated with considerable safety built into them. Therefore, using nitrox really does not yield superior results since, the incidence of DCS in recreational diving is already very low.
Best ideas are low activity on the bottom, some activity topside. Do not perform strenuous physical exercise topside, and drink water.


Dr Deco :doctor:

 

[mikeyjoe]

When diving on enriched air, I feel less tired in the evening, compared to when I dive on regular air. I know others that would say the same. Does it make everyone feel a bit better after diving? Probably not, but it does make a difference for me.

 

[Thalassamania]

Dr. Deco's advise is good, "Best ideas are low activity on the bottom, some activity topside. Do not perform strenuous physical exercise topside, and drink water." to which I'd add, consult a diving physician about taking a baby aspirin with a liter of water before the first dive of the day and a liter of water before every subsequent dive.

As far as EAN is concerned, I try to dive it whenever possible, I use the highest allowable mix and I dive air tables or an air computer. My results are purely anecdotal, but I feel like I have a good deal more energy at the end of a diving day when doing this as compared to when diving air on air tables (perhaps if I cut back on my tables in the the same way that I do for the EAN, thing might be similar ... I'll have to try that).

 

[DocVikingo]

Like Thalassamania I also feel less fatigued at the end of a day diving EAN to air tables. Of couse, there is no hard evidence for this effect.

Regards,

DocVikingo

 

[Dr Deco]

Hello:

Many divers have said that they feel better after nitrox. I have no idea but suspect that it might be somewhat of a placebo effect. Not that this is bad, mind you.

Dr Deco :doctor:

The next class in Decompression Physiology for 2009 is April 4 and 5. This class is on Catalina Island at the USC Marine Laboratory. Contact Karl Huggins at the web site: Advanced Decompression Physiology Seminar Information

 

[Web Monkey]

Hi Dr Deco - I've been diving for 35 years and although I have read a fair amount about Nitrox I never felt the need to go there.

As I am 62 now I was wondering if there are any advantages or disadvantages in going Nitrox for older divers?

You have about 10 years on me, but this might still be helpful.

When I first started diving, sometimes I'd be so tired after the dive that I almost fell asleep at the wheel.

Shortly after that I did four things at about the same time that made a huge difference in how I felt. Unfortunately because they were all about the same time, I can't tell you which was responsible.

• Switched to nitrox
• Started doing very slow ascents (less than 30'/minute) with even slower ascents (really, really slow) for the last 15'-20'
• Got a pee valve for my drysuit and now drink a liter of water while driving to the dive site.
• Started driving the car down to the water to load my gear instead of walking up the hill to the parking lot with steel tanks and weights.

Now I can finish a couple of dives and be ready to go out for the evening instead of thinking about pulling off the road for a nap on the hour drive from the lake to my house.

Terry

 

[Wayan]

You have about 10 years on me, but this might still be helpful.

When I first started diving, sometimes I'd be so tired after the dive that I almost fell asleep at the wheel.

From very first time I used NITROX and various mixes I hav dived with since I have not noticed any change in tiredness etc after the dive. I believe that a lot of the "I feel great syndrome" after using NITROX is psychological (which is ok if thats what you fell then great) wish it did the same for me.

No real disadvantages, as to a lower risk of DCS if you dive NITROX this is not quantifiable as the Doc Deco said the incident of DCS per dives is really quite low as it is now. You will still see people who have dived with NITROX in the Hyperbaric Units with DCS hits.

But anything you can do to minimize the risk is a good plan, generally it is not just 1 thing but a number if things that you change to reduce the risk, such as not diving as deep, reducing dive times, not over exerting oneself, staying hydrated, etc etc

 

[Reg Braithwaite]

Many divers have said that they feel better after nitrox. I have no idea but suspect that it might be somewhat of a placebo effect.

Two questions. First, is there any possibility that the phenomenon of divers reporting that they "feel better" even though there is no measurable decrease in DCS can be explained as Nitrox decreasing sub-clinical DCS symptoms?

I used Nitrox most of last year, and the few times I didn't use it, I definitely felt fatigued and had the sniffles. Then I was doing some reading and the subject of bubbles provoking an immune system response came up, and this seemed to explain my (anecdotal!) experience: I may have been feeling my immune system's response when diving air rather than any direct DCS symptoms.

This possibility also addresses the question of why some people report feeling no benefit when diving Nitrox. If we are not talking about actual DCS but rather we are talking about the body's immune system responding to bubbles in the blood stream, some people may be more sensitive to bubbles than others. In which case the answer might be, "if you are sensitive to bubbles, then Nitrox is important for you." is this conjecture reasonable?

Second, Nitrox does reduce the EAD, thus you get longer bottom times. True. But there's another factor I have not seen discussed outside of some technical manuals. When the dive is complete and you decompress, if you are diving Nitrox you have a slightly better gas gradient since the N2 partial pressure in your breathing gas is lower than air.

This is obviously a very big deal for divers using 50%, 80%, or 100% O2 as a decompression gas. But wouldn't breathing 32% or 36% Nitrox provide a small benefit to assist off-gassing more efficiently? To be specific, I am wondering whether the following is true: Given two identical divers, one on air and one on Nitrox, if both dive to their NDL at the same depth, I would expect their tissues to have the same amount of nitrogen at the completion of their bottom time. Now both ascend using the same protocol. I now expect the Nitrox diver to have less nitrogen in her tissues than the air diver because the gas gradient assisted off-gassing during the ascent.

I am probably over-thinking Nitrox here, but I have been wondering about this recently...