Nitrox?

[gmerick]

Perceived fatigue improvements may be attributable to differences in VO2 uptake. The diver that notes the improvement is likely the diver with a lower VO2 uptake. At the beginning of the dive that diver is likely breathing faster, and likely has an O2 sat in the mid 90s vice high 90s-100 for the other diver. This (again likely) carries through for the entire dive with the less fit diver pushing that extra bit to stay with the leisurely pace of the other. At the end of the dive, the cumulative effects of an hour spent with an O2 sat in the mid 90s will be fatigue. Simply breathing EAN32 for that hour will be noticed as less fatigue.

 

[freeflowigb]

I just did my nitrox course today and I generally dive within OW limits. Same today, we only went to 55 ft. I dunno if it is placebo or something else, but I felt unusually energetic after the dive, 32% nitrox. After that we did a regular air dive and for some reason it lasted me much less, and the usual post dive tiredness was back.

 

[formernuke]

Some feel that way, I'm also one of them.

 

[MidOH]

Download the instructions for any computer youre interested. Then again for the Shearwater Perdix or Terric.

After a few manuals, I found some extra cash quick.

 

[Blackcrusader]

I just did my nitrox course today and I generally dive within OW limits. Same today, we only went to 55 ft. I dunno if it is placebo or something else, but I felt unusually energetic after the dive, 32% nitrox. After that we did a regular air dive and for some reason it lasted me much less, and the usual post dive tiredness was back.

OW limits... the same as recreational depth limits... 40m.

 

[freeflowigb]

OW limits... the same as recreational depth limits... 40m.

In PADI, OW is only 18m/60ft max.

 

[dmaziuk]

 

[Fred Tagge]

Nitrox can have some long term benefits when used within its limits. Again this is a "local conditions" thing so the type of diving you do is important for the intensity of the benefits. A lot of divers with several thousand dives can end up with accumulated nerve damage from "silent" small DCS hits that are generally not treated because the diver is unaware of them at the time. Nerve damage is additive so lots of small hits eventually add up to the effects of a pretty significant single event nerve hit. There are a lot of older experienced divers with partial numbness in their feet from this effect. While not "serious" it can make going up or down stairs or ladders more interesting.
Nitrox works by artificially reducing your N2 absorption at depth. This does several things in the short term by either allowing a longer bottom time per day while staying inside the NDL, but it can also allow you a greater NDL safety relative to breathing air at the same depths for the same amount of time. This can be as great as about a 25% reduction in the possibility of an undeserved or minor hit when diving an appropriate nitrox mix for the depth and time involved.
As an example when spearfishing on oil rigs in the GOM maximum possible depths are generally over most commercially available nitrox blends, but by adding just 2 to 4% O2 to the mix, and then diving air tables it can help eliminate some really bad trips to the beach and the chamber ride. Big fish will take you where they will once tied onto them, and ascent rates with a finned DPV towing you can easily exceed what the training gods decree. Having a bit of a built in safety margin is a good idea there.
Off Panama City, FL the bottom has a very gentle slope. Most of the dive sites the half day boats take you to there are in depths where a 40% O2 mix will get you into trouble on a dive only if you bring a shovel. OTOH at that mix most of the diving there is in the "stay all day" NDL range if diving nitrox tables.
What benefits Nitrox brings you is not a constant, but it does allow you to tailor your gas mix to then maximize the safety or other concern the diver has, but at an increased co$t.