- Messages
- 19,951
- Reaction score
- 18,880
- Location
- Philadelphia and Boynton Beach
- # of dives
- 1000 - 2499
I have observed the work accomplished on quite literally thousands of dives as well as my own feeling and willingness to undertake evening activities or tasks at the close of the diving day. I defiantly have more energy when DIVING NITROX ON AIR TABLES.
Thal makes a very important point here. He feels better, perhaps even defiantly so, when he dives nitrox using air tables. This would certainly result in less nitrogen exposure and may be comparing differences in nitrogen exposure rather than diving gas.
I dive nitrox exclusively to prolong my NDL. I dive air or nitrox to the same limits, make the same ascents, and take the same safety stop or short decompression stop. I do get longer dive times using nitrox. Personally, I notice no difference in fatigue when using air or nitrox. One's feelings are subjective and I certainly respect the opinions of divers who report they are less fatigued when using nitrox.
The SB poll referenced in post #42 is interesting. Sixty percent of 205 respondents voted that nitrox made them feel less tired or more energetic whereas 40% of respondents stated that there was no difference. No one thought nitrox made them feel worse. Though hardly a scientific sample, perhaps even risking selection bias due to SB participation, the poll points out there is a reasonably even split concerning divers thoughts on this issue.
Perhaps because I am a physician, I tend to be evidence-based, perhaps even excessively so. Most people would agree that they would want the medications given to them for illness be judged as efficacious and safe by rigorously designed clinical trials rather than from anecdotal experience. I found the following, well designed clinical trial published in a respected peer reviewed journal. Note, that since the bottom time was the same for the two dive groups, the nitrox group had less nitrogen exposure than did the air group.
Undersea Hyperb Med. 2003 Winter;30(4):285-91.
Measurement of fatigue following 18 msw dry chamber dives breathing air or enriched air nitrox.
Harris RJ, Doolette DJ, Wilkinson DC, Williams DJ.
Hyperbaric Medicine Unit, Royal Adelaide Hospital, Adelaide, South Australia 5000.
Many divers report less fatigue following diving breathing oxygen rich N2-O2 mixtures compared with breathing air. In this double blinded, randomized controlled study 11 divers breathed either air or Enriched Air Nitrox 36% (oxygen 36%, nitrogen 64%) during an 18 msw (281 kPa(a)) dry chamber dive for a bottom time of 40 minutes. Two periods of exercise were performed during the dive. Divers were assessed before and after each dive using the Multidimensional Fatigue Inventory-20, a visual analogue scale, Digit Span Tests, Stroop Tests, and Divers Health Survey (DHS). Diving to 18m produced no measurable difference in fatigue, attention levels, ability to concentrate or DHS scores, following dives using either breathing gas.
PMID: 14756231 [PubMed - indexed for MEDLINE]
This is a very interesting topic, everyone's personal opinion or belief is valid. I doubt there will ever be sufficient scientific information to convince everyone, one way or the other.
Good diving, using nitrox or air, Craig