Nitrox?

[Blackcrusader]

Recreational dives for cruise ship passengers never go beyond 45, maybe 50 minutes on the very outside. Usually they are 35-40 mins.
At this stage in my experience I'm using up gas pretty fast, usually get low at about 35 mins.

I'm 185cm tall, a bit portly at 135kg, or one could say better insulated. So far I have done around 25 dives in the 11 days. The water temperature has been 26c or 27c and divers with me are getting cold. Had to insist my DM use a thicker wetsuit so he can keep with with my dive times lol Dived with this same DM for several years now. If we are doing 3 dives a day then average time is 70 minutes or more. Some dives are inter island day trips but when only two dives its because bad weather and coast guard telling dive ops they cannot do inter island trips.

If two dives 90 mins plus 80 mins on second dive. Max Depths are listed there as well.

 

[Blackcrusader]

25 hours under water in a week is simply not practical without NITROX.

I do it quite often. Some surface intervals are 90 or 120 mins though.

 

[Blackcrusader]

I cannot say I agree with this myself, I certainly feel less tired after diving on Nitrox, especially over 24 metres. Most people I dive with also think this. Personally I cannot see how anyone can disprove this claim, it is highly objective.

I Just accept what people tell me. I often do 35 - 40 dives in a 12 diving day trip. Some places don't offer nitrox some do. I feel no different with nitrox than without. However, I do eat well, keep myself hydrated and am normally asleep by 10:30pm and get in a solid 8 hours of sleep. Some people go party till 4am then come to dive shop at 8am for inter island trip spouting off how tired the diving makes them feel. lol

 

[Blackcrusader]

I appreciate the feedback. So far every dive I've done has been pretty simple and the DMs have always looked after the "old, new guy".

Last November I was in Bohol where I dive from time to time. My usual DM was not available for my dive trip so was assigned another. On several dives that old guy being me had to keep tab on the DM as the DM was the one low on air when I had near half a tank. You do not know if your DM got certified as DM the day before you dived with them. Do not assume that the title DM means the diver is really experienced.

Now for my SPG ( not suggesting you get the same unless you like spending money ) it shows depth, max depth, time, water temp, air and Range. Range means from the point of time on a dive to 50 bar or 750 psi. So lets say you want to make sure you can do a dive of 60 minutes and have 750 psi at 60 minutes. You look at the time dived already, and the range showing. Add the two together.


So on this dive after 31 minutes I have used about 30% of a tank of air. Range now shows that if I stay at 8m depth I can do another 67 minutes to 50 bar / 750 psi. This is a standard 80 cubic foot AL tank. So on this dive I could do another 90 minute dive to 50 bar / 750psi

 

[Eric Sedletzky]

Examples of fatiguing "narcotic" effects: alcohol, marijuana, morphine, heroin, hydrocodone, etc.
Basically, all the "depressant drugs". They all often make you feel tired or sleepy.

Also, the times that I have experience nitrogen narcosis specifically, I found experience highly fatiguing. So anything that reduces that nitrogen narcosis would also likely reduce the fatigue.

All of those drugs you listed are foreign substances that after entering the body need to be metabolized and processed/removed by the liver etc. and in many cases inflict damage upon the organs/tissues/ brain.
Atmospheric gases clear without trace and the narcotic affects are temporary that do not cause any permanent damage. However dissolved gases in solution that come out of solution too rapidly CAN cause nerve damage and subclinical DCS and yes, can lead to fatigue. But drug fatigue and gas caused fatigue are two entirely different things in how they cause fatigue.
BTW, if you want to ingest a foreign substance that most closely mimics the effects of diving narcosis, nitrous oxide is your best bet.

 

[dmaziuk]

Examples of fatiguing "narcotic" effects: alcohol, marijuana, morphine, heroin, hydrocodone, etc.
Basically, all the "depressant drugs". They all often make you feel tired or sleepy.

This may come as a shock, but... are you sure you're doing them right?

 

[jonhall]

everyone else who says they feel better after diving Nitrox is completely subjective.

This is empirical evidence which leads to further scientific studies and/or testing. Because it is not currently scientifically verified to reduce fatigue doesn't mean it won't be found to in the future.

placebo effect- because large numbers of people are convinced that they feel better,

I don't think anyone is saying nitrox affects everyone the same, only how they feel it affects them personally. The placebo effect might be an appropriate theory to apply here. It is about making a person feel better (since a placebo doesn't cure a person.) And if a diver believes they feel better using nitrox, what's wrong with that? The mind is a powerful thing.

clownfishsydney:
I cannot say I agree with this myself, I certainly feel less tired after diving on Nitrox, especially over 24 metres. Most people I dive with also think this. Personally I cannot see how anyone can disprove this claim, it is highly objective.

Going with the science, the claim can currently be disproved. Going with how divers who say they feel better - that can't be disproved!

 

[Marie13]

I just finished Simon Pridmore’s new book on the birth of tech diving in the 1990s. Reading about the “nitrox wars” was highly entertaining. That made me think of this thread.

 

[60plus]

This theory has been thoroughly debunked.

The above refers to the question "does nitrox make you feel better". As its just a feeling it cannot be debunked. My diving usually consists of 2 dives to over 30m in a day, each to the maximum time on a 15L tank. I definitely feel less fatigued when using nitrox. Common symptoms of decompression sickness (DCS) include extreme fatigue As nitrox makes DCS less likely it also near certain to reduce fatigue because it reduces the build up of nitrogen that causes fatigue. I have discussed this with a person who is a professor of Pharmacology, A fellow of the Royal Society of Pharmacologists and the former head of imaging sciences at a University. Her opinion is that raising the oxygen concentration will be beneficial. Not quite a direct comparison but consider the effects of EPO on athletes performance. The aim is to get more oxygen to the muscles.

 

[tursiops]

This theory has been thoroughly debunked.

False.