physiology Q3> diving, urination, and osmosis ?

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Salt

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The dive guides always ask us not to pee in the rental wetsuits. I understand the reasons for the recommendation but it always makes me laugh inside. I find this next to impossible. I suspect others to do. I usually have to pee 2 or 3 times per dive. I do try to rinse the wetsuit thoroughly before handing it back of course:wink:

I know the need to urinate occurs because of our body's attempts to maintain equilibrium. But I don't understand it other than that generalization. Is the sea water entering our body? or does our body need to use its own internal water to maintain some kind of electrolyte balance?

and the practical question> how important is it to drink fluids after diving to stay hydrated?

thanks.
 
Google "immersion diuresis". It is caused by decreased temperature and increased pressure.
 
Peeing, like amount of needed sleep, is an individual thing. I pee all the time and take medication for it. But yes, I pee even more when in water. Hydrating: I've always read it's best to stay hydrated. Before I developed a decent method to pee my wetsuit I would hold it (not very comfortable for me) and drink at most a small mouthfull of water (or none at all) before a dive. Why make the pee problem even worse? No problems with that yet. I guess I wasn't hydrated much at all?
 
Dehydration is a doctor leading to potential DCS. Don't stay thirsty, stay well hydrated my friends!!!
 
Immersion diuresis remains a mystery to me. I have done more than 200 drysuit dives in +4C and I do know one person that suffers from immersion diuresis... I have never had that problem. I do not drink 1h before a dive and I enjoy cool temperatures. Hence, it must be a personal thing. Some people are less affected while others suffer horribly. Don't know how immersion in water affects. Haven't used wetsuits...

---------- Post added May 27th, 2014 at 01:04 AM ----------

Have you considered using a surfers heating belt? It would warm up the kidney area and deliver warmth...
 
I do know one person that suffers from immersion diuresis...
I don't suffer from it, but if I don't pee a couple of times on a 45 to 60 minute caribbean dive I figure I'm not adequately hydrated


It would warm up the kidney area and deliver warmth...
I don't see that warming the kidneys would help. Cold extremities and pressure both result in moving blood from the extremities to the core. To your body's control systems that's the same as having a higher blood volume, so in a healthy person the common result is a body that attempts to reduce blood volume. That's done by increasing kidney function and producing more urine.
 
Is the sea water entering our body? or does our body need to use its own internal water to maintain some kind of electrolyte balance?

and the practical question> how important is it to drink fluids after diving to stay hydrated?

Seawater would not enter your body unless you were drinking it. I don't think there is any significant increase or decrease in electrolytes while diving. The increased need to urinate occurs because of the increase in pressure and decrease in temperature underwater.

Also, I've seen the Mythbusters test this -- that dipping a person's hand in a bowl of water while he was asleep causes him to urinate involuntarily. While the Mythbusters "busted" that myth, Youtube has a lot of other instances that shows otherwise. Some have said it's due to the power of suggestion.

It is important to stay hydrated because dehydration causes tiredness and can lead to decompression illness.
 
It has to do with the fluid redistribution that occurs when the body is immersed. The effect of gravity goes away, which causes about 600-odd cc of blood to be redistributed to the blood vessels in the torso. The kidneys see this and take steps to eliminate the "excess" fluid.

Best regards,
DDM
 
https://www.shearwater.com/products/swift/

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