I'm currently about 30 lbs overweight. I'm also generally much warmer than many others around me, and am constantly seeking ways to cool off. I'm already working on slimming down, but I'm wondering - if I lose 30 lbs and reach my target weight, will I be significantly cooler as well? How much difference does fat make in regulating one's body temperature?
From personal experience, I can say that you will lose some insulation when you lose fat, but that may not change much for you. I lost around 85 pounds of fat, and I can say that I get really cold in the winter. My hands are almost always ice cubes, but my thyroid tested out OK. I have to button up my jackets now, but now I can so it's OK.
I've always run a bit cooler than most people, seeking ways to stay warm. My basic physiology is a bit different than yours. You'll probably still be looking for ways to cool off, but you won't have to work as hard to do it.
Insulation traps body heat in, and slows the effect of the outside environment. What you will see is that with less fat (insulation):
- If you are already cold, it will take less time to warm up when you go outside.
- If you are already hot, it will take less time to cool off when you go where there's air conditioning.
Surface Area vs Volume Not only does fat provide insulation...it also affects a body's surface area-to-volume ratio.
Volume represents how many cells are in a body (and cell size, like in fat). Larger and more numerous fat cells means more volume.
It also means more surface area. But because surface area grows at a square rate and volume grows at a cube, your volume-area ratio will get tipped as you gain fat or muscle.
Because we cool our body via an evaporative process on our skin (surface area), if volume goes up 70% and surface area goes up 30%, we'll have increased the thermal load without a commensurate ability to cool.
Sweat Glands vs Volume Also, your sweat glands don't increase as you skin stretches to accommodate a larger body. A larger body doesn't have more sweat glands for a larger heat load.
Thus it's more difficult to cool a fat body than a skinny body.
I have kept tabs on various body particulars, including daily records of weight,(160) fat (currently 9.5%, moisture (64.5%), heart rate (42) at different times, and blood pressure (range from 112/58 to a high of 229/127) from March 26, 2006 to the present day. I am a distant runner and Decathlon competitor, which includes weights, speed work and of course forms and plyometrics. Recently, due to an injury, my exercise regime went from a high of 35 miles down to nothing. Then, I had the misfortune of falling off the roof. Stuck the landing, but bleed quite a bit. Anyway, things are improving. There is a phenomena called Wilson's syndrome in which the body temp is less than 98.6. When air temp gets below 45 degrees, the body temp goes down. With a 9.5% number, I have had usually a number in the range of 95-96F, but a recent cold spell, and not working out, had me down to 90.2. Death from hyporthermia supposedly occurs at 89F. But, I was fine. There were no symptoms of shaking or cold body parts or whatever. I'm running today. I have recently speculated that there is a defined ratio of air temp, and body fat, that allows it to slide down to 90, without problems.