Nitrox for Liveaboard - Great Barrier Reef

[tarponchik]

@tursiops Of course, anything you won't find in PADI manuals must be a conspiracy theory.

 

[tursiops]

If there is a fact I can give my own explanation to this fact.

This explains a lot....

 

[LI-er]

If there is a fact I can give my own explanation to this fact.

This is the most sensible thing you've posted on this thread.

 

[tarponchik]

Increased partial O2 pressure (pO2) promotes oxidative stress, which triggers endothelial dysfunction....High pO2 may also promote oxidative stress due to the hyperbaric environment, increasing free O2 that may generate ROS [109]. . Neopterin and creatinine levels increase, which suggests an alteration in renal function as a physiological response to pO2 variations during the dive [109,110]....SCUBA diving-related physical activity can induce oxidative and cardiovascular stress, amplified by environmental conditions, including hyperoxia, hyperbaric pressure, and cold water [131,132].

I apologize, this language may be too scientific for you guys. I highlighted words that you might know.

 

[LI-er]

I apologize, this language may be too scientific for you guys. I highlighted words that you might know.

You clearly have no understanding of what you read and propagate these ridiculous ideas based on your misinterpretations of the subject matter.

 

[tarponchik]

You clearly have no understanding of what you read and propagate these ridiculous ideas based on your misinterpretations of the subject matter.

So far I haven't heard a single rational argument from you. What's your problem with understanding the meaning of the phrase "Increased partial O2 pressure (pO2) promotes oxidative stress"?

 

[LI-er]

So far I haven't heard a single rational argument from you. What's your problem with understanding the meaning of the phrase "Increased partial O2 pressure (pO2) promotes oxidative stress"?

According to your theory we should all stop breathing compressed air or else risk premature death.

Do you seriously believe divers are living shorter lives than non divers?

 

[Sascha314]

Drawback of Nitrox certainly are deeper dives. If I know the max depth, Nitrox will give me benefits - well keep an eye on your max oxygen exposure though.
But of course I put in a risk of getting too deep, if I am not careful and use a nitrox with high o2 concentration.

However this recent discussion about oxidative stress with high ppO2 .. if that where to be of a high concern within the usual ppO2 limits, that would first be an issue for rebreather divers.
In OC you will not likely do a dive profil with decending to max depth, stay there for maximal time and ascent directly. So the oxygen exposure is in most cases less than for rebreather divers, who have a setpoint somewhere I would put my MOD.
If I use a higher MOD or violate it, that may be a different story. For this possibilty I would suggest air or lower oxygen concentration

 

[boulderjohn]

Increased partial O2 pressure (pO2) promotes oxidative stress, which triggers endothelial dysfunction....High pO2 may also promote oxidative stress due to the hyperbaric environment, increasing free O2 that may generate ROS [109]. . Neopterin and creatinine levels increase, which suggests an alteration in renal function as a physiological response to pO2 variations during the dive [109,110]....SCUBA diving-related physical activity can induce oxidative and cardiovascular stress, amplified by environmental conditions, including hyperoxia, hyperbaric pressure, and cold water [131,132].

I apologize, this language may be too scientific for you guys. I highlighted words that you might know.

Here is the link to the whole article.

It is a complex article citing many sources. It also presents a complex situation. Take, for example, this quote:

Dumić et al. [147] reported that regular recreational SCUBA diving promotes an anti-inflammatory status, thus contributing to cardioprotection and conferring multiple health benefits. Divers who performed five dives, one per week, at a depth of 20–30 m that lasted 30 min, manifested IgG and TPP N-glycosylation alterations toward anti-inflammatory status over the whole study period with an increase in monogalyctosylated and core-fucosylated IgG N-glycans and a decrease in galactosylated TPP N-glycans. On the other hand, military combat swimmers (O2 divers) are regularly exposed to hyperbaric hyperoxia in addition to intensive endurance training intervals and, therefore, are exposed to extreme levels of oxidative stress. Compared to controls, they exhibited a proinflammatory immune status exemplified by an elevated number of CD4+CD25+ T cells, the elevated expression of proinflammatory cytokine IL-12, and the diminished expression of anti-inflammatory TGF-β1 [148]. Supported by decreased basal gene expression and the prolonged upregulation of anti-oxidative HO-1, these data suggest that higher oxidative stress levels, as those present under intermitted hyperbaric hyperoxia conditions, e.g., through oxygen diving, promote a higher inflammatory immune status.​

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The paper's focus on problems with high oxygen pressures is dealing with very long exposures to very high PPO2s, something that has been well understood for many decades. They reference prolonged exposures to PPO2s of 1.0 or above. Technical divers are taught to take air breaks when doing long decompression stops using pure oxygen. People doing decompression therapy in a chamber also take periodic air breaks.

 

[tarponchik]

According to your theory we should all stop breathing compressed air or else risk premature death.

Do you seriously believe divers are living shorter lives than non divers?

This is your theory, not mine.