Divetech99
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Thanks. Agree with you. Just don't know why the myths of lower air consumption and less fatigue continues to permeate. Placebo effect probably.
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DAN says "no"
Alert Diver | Air, Nitrox and Fatigue
"Despite a common impression that diving on nitrox may cause less fatigue than performing the same dive using an air mixture, scientific research to date has not found solid evidence to support such an assumption."
This article says "no"
Harris RJ, Doolette DJ, Wilkinson DC, Williams DJ (2003). "Measurement of fatigue following 18 msw dry chamber dives breathing air or enriched air nitrox".Undersea and Hyperbaric Medicine (Undersea and Hyperbaric Medical Society) 30 (4): 28591. Measurement of fatigue following 18 msw dry chamber dives breathing air or enriched air nitrox.
"Diving to 18m while breathing air produced no measurable difference in fatigue, attention levels, ability to concentrate or DHS scores, compared with breathing EANx 36%."
This article says "no"
Chapman SD, Plato PA. "Measurement of Fatigue following 18 msw Open Water Dives Breathing Air or EAN36.". In: Brueggeman P, Pollock NW, eds. Diving for Science 2008. Proceedings of the American Academy of Underwater Sciences 27th Symposium. http://archive.rubicon-foundation.org/xmlui/handle/123456789/8005
"Results from this study did not support the contention that using EAN36 as a breathing gas reduces post-dive fatigue. To date, research has indicated that there is no difference in fatigue levels between air and EAN36 dives."
The rate of DCS is less than .01% using air. Using Nitrox lowers that risk. It isn't much lower but if it makes divers believe they're safer they use it. I prefer to use it for accelerated deco gas only.
Thanks. Agree with you. Just don't know why the myths of lower air consumption and less fatigue continues to permeate. Placebo effect probably.
Measurement of Fatigue following 18 msw Open Water Dives Breathing
Air or EAN36
Scott D. Chapman, Peggy A. Plato
Department of Kinesiology, San Jose State University, One Washington Square, San Jose, CA 95192,
USA
scott_chapman@wvm.edu
plato@kin.sjsu.edu
Discussion(my excerpt from)
The purpose of this study was to compare fatigue levels between two test sessions consisting of two
repetitive dives breathing either air or EAN36 in an open water environment. It was hypothesized that
the reduced nitrogen level and subsequent higher oxygen levels would lead to decreased fatigue
Rubicon Research Repository
9
following two repetitive EAN36 dives. Analyses of reported fatigue failed to support this premise;
however, scores on the Diver Health Survey did exhibit a significant decrease following dives using
EAN36 compared to air.
Measurement of Fatigue following 18 msw Open Water Dives Breathing
Air or EAN36
Scott D. Chapman, Peggy A. Plato
Department of Kinesiology, San Jose State University, One Washington Square, San Jose, CA 95192,
USA
scott_chapman@wvm.edu
plato@kin.sjsu.edu
Abstract
SCUBA divers often report feeling fatigued upon conclusion of diving activities. Post-dive
fatigue is thought to be induced by increased energy demands of submersion in a hyperbaric
environment and decompression stress. Anecdotal reports indicate a reduction in post-dive
fatigue when using enriched-air nitrox (EAN). The purpose of this double-blind study was to
compare subjective fatigue levels experienced by SCUBA divers after two repetitive air dives
and two repetitive EAN36 dives on separate, nonconsecutive days. Eleven male participants
completed pre- and post-dive fatigue assessment using the Multidimensional Fatigue
Inventory and a Visual Analogue Scale, while general health was assessed using the Diver
Health Survey. Divers did tend to be more fatigued after diving; however, breathing gas
mixture exhibited no statistically significant effect. Participants did have significantly lower
Diver Health Survey scores upon the conclusion of EAN36 test sessions, possibly indicative
of reduced decompression stress.
It seems reasonable that people "feel better" after using nitrox, even if they just as fatigued as they would be using air.
It may of course be pure, unadulterated placebo, but I've found that diving less aggressive profiles reduces post-dive fatigue. Proper multi-level profiles instead of square profiles, a good safety stop, ascending on a (dSMB) line instead of just corking from the SS or using nitrox, particularly on deep or repeated dives, all seem to reduce my post-dive fatigue. Since post-dive bubbles have been shown to be prolific even in DCS-asymptomatic divers, I'm pretty convinced that nitrogen loading induces a stress on the body, even if you don't exhibit DCS symptoms.