Body core temperature and Diving

[Diver-Drex]

Having cold hands and feet, seems to me logical but not related that much of core temperature because does are the body parts with less flesh and blood circulation so the water temp will affect them first, if one start to shiver that is a indication that your core temperature has been compromised, you shall never get to that point, probably not the right amount of thermal protection.

@Remy B. - When the body detects that it's core temperature is dropping blood flow to the extremities (hands and feet) is reduced. The body does this in an attempt to preserve heat. So cold hands and feet, while not always the case, are a very good indicator that your core temperature is dropping.
The theory is that the same reduction in blood flow also reduce perfusion and thus increases DCI risk.

D

 

[Beau640]

I guess a question that comes up is; When someone is more tolerant to cold, is it that they truly don't get cold as easily, or they are able to endure being colder than others?

This is an interesting question. When someone says they can dive in the cold without getting cold, is that because they are tolerant of colder core temps before having the sensation of cold, or are they actually more efficient at maintaining their core temp and so have a delayed onset of cold sensation and shivering. I'd have to look that up.

in terms of the vasoconstriction to hands and feet: as your core temp drops, your body shunts blood away from the hands and feet to its core to help preserve heat to vital organs (at the expense of losing extremities. Body has decided it would rather loose a foot than a kidney). The thought is that this applies to decompression because if you vasoconstrict and shunt blood away from the extremities, you decrease decompression efficiency since those tissues can not as easily off gas now since they no longer have adequate blood supply.

In theory from a decompression standpoint, optimally you would want to be cold during the bottom of a square profile to decrease tissue on gassing, and then instantly warm and vasodilated when you ascend to increase tissue offgassing efficiency.

 

[MegDiver792]

I dont tolerate cold at all. I'm dressed up like the Michelin tire man, including heated vest and argon.Now this is for 3+ hour dives in low 40's high 30's at the worst. I also dive vpmb+3, never taken a hit in 4 years of tec diving most every weekend. My heater is on from start of dive to end.