Diving "Conservative" vs Nitrox

[RobPNW]

The oxygen partial pressure while diving on air is often higher than that administered in hospitals. Picture filling a bucket with a small hole in the bottom. When it's full, it's full, no matter how fast you fill it (assuming a minimum rate not lower than your metabolic rate).

So based on this logic, doing oxygen therapy for DCS on the boat is purely to displace new ongassed nitrogen vs any benefit of added oxygen in the body?

 

[rjack321]

So based on this logic, doing oxygen therapy for DCS on the boat is purely to displace new ongassed nitrogen vs any benefit of added oxygen in the body?

Zero on-gassing, maximum off-gassing, and tissues potentially blocked of oxygen (by a bubble) might get a smidge more via diffusion from nearby better oxygenated tissues. The latter doesnt really kick in until you're under hyperbaric conditions.

 

[boulderjohn]

I think it is time for @Duke Dive Medicine to step in.

 

[RobPNW]

I think it is time for @Duke Dive Medicine to step in.

Hey just curious about forum mechanics, if you call out a person with their username like this, do they get a notification?

 

[boulderjohn]

Hey just curious about forum mechanics, if you call out a person with their username like this, do they get a notification?

yes

 

[inquis]

@Dr Simon Mitchell recently posted a nice primer about O2 uptake in another thread that may clarify how our physiology works.
Why doesn't oxygen cause decompression sickness?

 

[Comm]

@Dr Simon Mitchell recently posted a nice primer about O2 uptake in another thread that may clarify how our physiology works.
Why doesn't oxygen cause decompression sickness?

This is an incredible thread. One of my favorites to date

 

[tursiops]

the science does not support that conclusion as far as I know

Nor does it deny it. Decent science has NOT been done on the issue. I'm forced to go with what my body tells me; I'm less tired diving Nitrox. YOUR personal experience is irrelevant to me.

 

[fred32176]

Hey fellow divers,

I've been pondering the choice between conservative diving and diving with Nitrox, and I'd love to hear your thoughts and experiences on the matter.

For those who may not be familiar, conservative diving typically involves adhering strictly to no-decompression limits and safety stops, often using air as the breathing gas. On the other hand, Nitrox, also known as Enriched Air Nitrox (EANx), involves diving with a higher percentage of oxygen than regular air, which can extend bottom time and potentially reduce post-dive fatigue.

I've found both approaches have their merits, but I'm curious about your preferences and the factors that influence your decision when choosing between them. Do you lean towards one method over the other depending on the dive site, conditions, or personal preferences?

Personally, I appreciate the added safety margins of conservative diving, especially when exploring unfamiliar sites or diving in challenging conditions. However, I've also enjoyed the extended bottom times and reduced nitrogen loading that Nitrox offers, particularly on repetitive dives or when diving deeper.

So, what are your thoughts? Which approach do you typically prefer, and why? Have you noticed any significant differences in your diving experiences when using one method over the other? Let's dive into this discussion and share our insights!

Looking forward to hearing from you all.

Happy diving!

I just bought a pair of steel 100's and plan on keeping them filled with nitrox. I plan on using nitrox on every dive. If I knew of a downside to using nitrox, I would consider using air on some dives. But I have not heard of any downside to nitrox (if you don't exceed your MOD).

I have only used steel 100s a few times and fell in love with using steel 100s and bought a pair because I love them. I have used nitrox a few times and have liked diving with nitrox. 100's and nitrox are tools for letting me enjoy a longer dives.

 

[Duke Dive Medicine]

I think it is time for @Duke Dive Medicine to step in.

Thanks for the add John. Not much additional to contribute; Neal Pollock and Richard Harris sum it up pretty well in the DAN article. I'm not aware of any peer-reviewed literature that compares increasing computer conservatism with breathing EAN for the same dive profile. Changing gradient factors adds another dimension to this question and makes it even harder to study. Some studies that have been done since the 2014 DAN article, for what they're worth:

A 2020 study that used 40% nitrox, possibly one of the ones that @boulderjohn mentioned with a relatively small n (13):

Does oxygen-enriched air better than normal air improve sympathovagal balance in recreational divers?An open-water study - PubMed

Effects of the hyperbaric environment on the autonomic nervous system (ANS) in recreational divers are not firmly settled. Aim of this exploratory study was to (1) assess ANS changes during scuba diving via recordings of electrocardiograms (ECG) and to (2) study whether nitrox40 better improves...

pubmed.ncbi.nlm.nih.gov

A 2016 study on divers who bubble a lot, which should be interpreted in the context of the study on the high degree of variability in venous gas emboli cited by Dr. Mitchell in another recent thread:

Enriched Air Nitrox Breathing Reduces Venous Gas Bubbles after Simulated SCUBA Diving: A Double-Blind Cross-Over Randomized Trial - PubMed

ISRCTN 31681480.

pubmed.ncbi.nlm.nih.gov

Best regards,
DDM