How does the body stay cool in a hot bath?

[Astro Pen]

I was lying in a hot deep bath and though "Why is my body not heating up toward bathwater temperature?"
I have read a few replies on how the body maintains 37 degrees in a hot bath. Most say vasodilation and perspiration. But I don't think either of those quite make sense. So how is all the absorbed heat dissipated to keep you cool?

 

[HareBrain]

This question has occurred to me too. But what temperature is a bath at the point above which you can't lie up to your neck in it? Is it much more than body temperature?

 

[elvet]

There are many mechanisms for thermoregulation. First we have an insulating layer of fat and subcutaneous tissue.Then there is sweating response, we can lose a lot of heat through the scalp (very vascular). Physiological factors would kick in--vasodilation to parts of the periphery not submerged (head and neck, arms, etc.) If we're there long enough, our own heat generating mechanisms can slow down.
Being someone who enjoys a hot bath, but also gets hot flashes, I can be sitting in the tub quite contently, but all of a sudden get overheated to the point of turning the cold shower on. I guess what I'm saying is that your body compensates fine, but when you are in danger of being too hot, it will let you know.

 

[Alex The G and T]

Sometimes when spending too long in too hot water; you just have to get out and roll in the snow.

 

[Yozh]

Even a very hot bath is not that much hotter than body temperature (water heaters typically set at 140 F/ 60 C maximum), and as soon as that water comes out the tap it's losing heat to the surrounding air and tub which are likely in the range of 65-80 F/ 18-27 C. The a person gets in and sucks more of the heat from the water into their own 98 F / 37 C body, with the human and the bathwater both still also losing heat to the air and the tub. It's more of a wonder that a person stays comfortably warm long enough to have a relaxing bath, unless the tub itself has a heater.

 

[Swank]

At some point, you don't. More than a few people have died in hot tubs after their muscles stopped working and then they died of heatstroke.

Also consider the "wet bulb temperature" - the combination of air temperature and humidity that prevents perspiration cooling from working.

 

[Swank]

It is also interesting how you can put a roast in the oven for 2 hours at 400F and the internal temperature is 160F. Clearly, meat doesn't conduct heat like metal does.