Sold On Nitrox

[RobPNW]

Good advice here from the OGs. I tend to be the last one in and the last one out, mainly because I don't want to get caught up in the traffic coming in and out, and also because my knees aren't what they used to be and I don't want to be the guy holding up the process. That typically means I finish my 5 minutes in the shallows a few minutes before actually getting out of the water. I guess I have another reason to continue that practice.

 

[Rilelen]

I've always wondered if divers who start using Nitrox and find it reduces exhaustion etc might just be confounding it with those other factors (like longer safety stops). That is, might experience be the underlying third variable? More experienced divers tend to have lower SAC rates, move less in the water, be more conservative about NDLs/safety stops etc - I found my dives naturally became less tiring over time, on plain air.

And, since most people don't get their Nitrox certs right away, it's likely that people start using nitrox right around the time that their diving would be getting less tiring anyway.

I don't personally notice a difference, even on those 4-5 dives/day, weeklong dive trips...at home I do usually fill my tanks with nitrox just bc it's cheaper (I pay by the cubic foot for nitrox, as opposed to a flat rate for air fills, and don't tend to use much gas....).

It's been a very long time since I felt that "knockout-post-dive exhaustion," and wouldn't consider it normal unless I've been doing something unusually strenuous (that I prob would've found tiring above-water anyway!).

 

[b1gcountry]

Im a northerner. The sun makes me tired. Add travel stress to tropical destinations and the shallow shore dives will tire me out more than deeper dives in cold places.

There are a lot of variables is all im saying...

 

[MaxBottomtime]

I will add that a slow ascent is the most important part of a dive. I've seen too many divers race up to fifteen feet to begin a safety stop. Nitrox allows for longer NDLs or shorter surface intervals. There is no magic elixir blended within it.

 

[kaylee_ann]

Most divers who do a 3 minute or less safety stop, aka safety pauses, get that post dive exhaustion.


Yeppers. Glad to be of service, ma'am.
Yes, you do. O₂ is as narcotic as N₂. Narcosis can be exacerbated by cold, dark, stress, and unfamiliarity. The only relief is to ascend until it passes.

Thanks for the clarification I always say narcosis to refer to nitrogen narcosis, and oxygen toxicity rather than narcosis. It’s a bad habit of abbreviating things.

Exactly.

NitrOx has a number of nicknames, but Geezer Gas is my favorite. If you're over 40, your cells have begun to lose elasticity, which makes it harder to get rid of excess N₂. Less in means less to get out.

Apparently my body thinks it’s well over 40 if I’m exhausted from a 15-20 ft, 20-ish minute dive, if even that…hah. Maybe it’s sleep deprivation? Stress?

In addition, different tissue types ongass/offgas at different speeds with Neural and Blood tissues having the fastest at @ 5 minutes.

5 minutes.

So, doing a full five-minute safety stop allows fully half of the excess nitrogen to leave your neural systems. But, why not just surface and do it on the hard? Well, once N₂ starts to come out of solution (micro-bubbles), it gets increasingly hard to get rid of. N₂ is tolerable. N₂ as micro-bubbles is bad. The less N₂ is in your blood, the less likely it is to produce micro-bubbles. Think of it as surface narcosis in that it dulls your senses.

I’m hoping this makes sense somewhat, I’m sick and sleep deprived.
But I’d think since the pressure difference at shallow depths is more significant than when you’re deep, then coming right to the surface from, say, 25 feet would give you even more deco stress. So stopping in shallow water to let yourself offgas more inert gas slowly would avoid some of that shock on the surface. If that makes sense.

Probably way off the mark, but hey, fun thinking exercise

The best way to clear excess N₂ is to go on O₂ during your safety stop. But, you'll have to take extended range to do that.

Extended range would be a fun class to take! Someday I’ll get into that. Maybe. If it’s warranted for me

 

[MaxBottomtime]

Apparently my body thinks it’s well over 40 if I’m exhausted from a 15-20 ft, 20-ish minute dive, if even that…hah. Maybe it’s sleep deprivation? Stress?

New divers also tend to swim a lot, sometimes using their hands. They cover a lot of ground in a twenty minute dive. It takes practice, but slowing down to look at the small stuff helps with fatigue.
Diving is more physical than most realize. Gearing up takes a toll, as does following a DM or group. Climbing ladders or exiting from shore carrying 60-100 pounds of gear wears you out as well.

 

[kaylee_ann]

And the more I dived the slower I swam because it's not a race.

One benefit too is you may see some super interesting things that fast-swimming divers miss. “Stop and smell the roses” haha.

Another thing is that if you can avoid it, don't rush to get out of the water and climb the stairs or ladder with all that stuff on. It's why I love sidemount. Especially in lakes and quarries. I don't get out of the water with my cylinders. Clip them off to the drop line, get out with the just the harness.

Mhm, yeah, here’s what my post-RI dive looked like:
I speed-walked from the water up the semi-steep ramp to the benches with all my heavy-ass gear. Then had to put the gear away (obviously) in the back of a pickup truck soon after.
Fun
Maybe I don’t need to floor it to the benches. Lol.

 

[kaylee_ann]

New divers also tend to swim a lot, sometimes using their hands. They cover a lot of ground in a twenty minute dive. It takes practice, but slowing down to look at the small stuff helps with fatigue.

Ooh, good point! I don’t use my hands, but I naturally kick fast. I’m also a natural speedwalker; maybe they’re related somehow. It’s a problem when diving relies heavily on a buddy system. Gotta work on slowing down for quite a few reasons.

Diving is more physical than most realize. Gearing up takes a toll, as does following a DM or group. Climbing ladders or exiting from shore carrying 60-100 pounds of gear wears you out as well.

I commented in a prior post how I’d walked quickly up a ramp to the benches near the truck in full gear. Heavy steel gear that was soaking wet. Not fun. Guess it was just automatic

 

[kaylee_ann]

I will add that a slow ascent is the most important part of a dive. I've seen too many divers race up to fifteen feet to begin a safety stop. Nitrox allows for longer NDLs or shorter surface intervals. There is no magic elixir blended within it.

Not sure that a 5-10 minute stop at 15 ft is gonna do much to offset the decompression stress from their crazy ascent. Racing to the stop depth significantly lessens the benefit of it.
Probably depends on their ascent rate and depth/dive time.
At least that’s my train of thought.

 

[BRT]

I will add that a slow ascent is the most important part of a dive. I've seen too many divers race up to fifteen feet to begin a safety stop. Nitrox allows for longer NDLs or shorter surface intervals. There is no magic elixir blended within it.

Nitrox can allow for longer NDL's plus shorter surface intervals plus leaving more time before NDL's. Not magic, physics.