snorkling

[Garf]

Originally Posted by A. Berk

Steve, I am on your side with your original OP but that above is a load of ar5e. The stimulation to breath is effected when hyperventilation is practised beforehand. After a normal breath, that stimulation will occure at the same rate as O2 is consumed and you'll hit surface gagging for breath. Black-out is caused by the PO2 falling through your boots because CO2 has been flushed before breathhold through hyperventilation.

Berko

spot on

shallow water blackout. What happens is that when you hyperventilate, you reduce the level of CO2 in your body to an artificially low level. you then go diving. Your body metabolises the oxygen and the Co2 levels start to rise. They take longer than normal to rise to the level that would cause the urge to breathe becuase they start at a lower level. Meanwhile, your body is using up more Oxygen than it normally would becuase you are holoding your breathe longer. This is not a problem when you are at depth as the PPO2 means your body can still metabolise the remaining Oxygen. As your head for the surface however, the PPO2 drops below the point where your body can metabolise it, and you expeirence hypoxia and blackout.

[A. Berk]

Originally Posted by Garf

spot on

shallow water blackout. What happens is that when you hyperventilate, you reduce the level of CO2 in your body to an artificially low level. you then go diving. Your body metabolises the oxygen and the Co2 levels start to rise. They take longer than normal to rise to the level that would cause the urge to breathe becuase they start at a lower level. Meanwhile, your body is using up more Oxygen than it normally would becuase you are holoding your breathe longer. This is not a problem when you are at depth as the PPO2 means your body can still metabolise the remaining Oxygen. As your head for the surface however, the PPO2 drops below the point where your body can metabolise it, and you expeirence hypoxia and blackout.

Thaaaaaaaankyu Garf, I was hoping someone would come along and explain it correctly with words like metamorphmetabilationising and hippypoxed-up and stuff

kroBe

[David P]

The biggest overall lesson is still the usual one; don't push the limits! Relax, enjoy, take care.

[Daz217]

I like to snorkel in the surface interval or at the termination of the days diving when diving blue water. Again get some great photos in the shallows. Never really bothered in the UK suppose the faff of suiting up as opposed to jumping in in your trunks may have something to do with that I started out snorkelling on my summer holidays in the Med when i was 12 years old thats what eventually sparked my interest in life under the sea and me into diving in my early 20's when i was working and could afford to learn and buy my gear.
If i could not dive i would still continue to snorkel but only on holidays.