Can O2 hits reoccur on a dive

[Dr Deco]

Hello scubaado:

I am currently having a problem with a herniated cervical disk. I have trouble typing; please bear with me. Dr D.

Oxygen Toxicity

All living creatures on this planet are poisoned by oxygen-derived substances, and all have developed enzymes to protect against an accumulation of these. It is surprising to think of oxygen as a poison, but it is true.

Our cells have antioxidant enzymes such as superoxide dismutase, catalase, etc. They are generated within the cells in fixed amounts. Because of this natural limit, they can be “overwhelmed” if too much oxygen in present. Oxygen’s toxic effects manifest when this limit is exceeded. For reasons that are unclear, the limit seems to vary from day to day within an individual.

Induction

The protective enzymes cannot be induced when oxygen concentrations are increased. This means that the cells will not generate more in response t elevated oxygen partial pressures in the cells. Were this possible, you could increase your tolerance for oxygen when you breathe increased partial pressures of it.

Therefore if one gets an oxygen “hit,” you will not be able to safely stay at that partial pressure; it indicates that your have exceed the protective effect of the enzymes and cannot induce their concentration further.

As others have indicated, oxygen tolerance varies, and the “tolerance test” is no longer administered.



Dr Deco :doctor:

 

[fisherdvm]

To those that just want to unload testosterone, I asked a question to learn. If you don't know what the mechanism is, don't posture. how does O2 hit work, READ the details I specificly said FULL FACE MASK. so drowning is not the question. this is why I don't come here to often anymore. all chest puffing little info

For the few here with testicular tumors, they tend to post 85% of the posts. But the 95% of the folks who are helpful, are still here. Learn to ignore those posters, and you get great information here. I've gotten so much good advise, it is like taking OW from 10 different instructors... And Dr. Deco, he is always very objective and not condescending at all.