Body temperature regulation following vigorous exercise

[bibliophage]

For about 24 hours following vigorous exercise, I find that rather cool weather feels exceptionally cold and rather warm weather feels exceptionally hot. Does anyone know what causes this, and what I can do to prevent it?

For example, the other day I hiked two mountains. It took me about 4 hours (I’m about 30% faster than the average hiker). As usual with such hikes, I sweated profusely and drank a fair amount of water (about 3 pints). When I finished the hike, I felt a bit warm, but not very bad (the temperature was about 80ºF). Just after the hike, I ate a snack (about 300 calories) and some more water (one or two pints). I had a normal meal when I got home a few hours later. The trouble started a few hours after that. The low temperature that night was 60º and I needed to close the window and use two blankets. The next day’s high was only about 80º but I felt terribly hot. It wasn’t until about 24 hours after finishing the hike that I felt normal again. This sort of thing happens every time I go on such a long hike (three or four times a year). I am not exactly a couch potato; I usually walk two miles every day.

Should I be taking potassium chloride and/or sodium chloride before, during, or after the hike? If so, how much? I can see where that might make me feel hot (if a shortage of the electrolytes makes me unable to sweat normally), but I can’t see how that would make me feel cold. If you tell me that Gatorade will solve all my problems, I might actually consider using it (although I truly despise the taste of it). And something I just thought of: Is there any chance aspirin could be the culprit? I always take aspirin after such a long hike to combat soreness and stiffness.

[Yeah]

I've never heard of anything like what you complain of. I don't see why your electrolytes should be out of whack or why, if they are, that should affect your sensation of ambient temperature.

Aspirin sounds like a far out possibility since it can apparently affect temperature sensation in lizards. (A study of lizards showed that if you give them an experimental infection they will spend more time in the sun so that will "run hotter" than usual but that this repsonse to an experimentally induced infection does NOT occur if you pretreat them with aspirin.)

It would be interesting to compare your 24 hour temperature curve on "normal" days (when you haven't been on a vigorous hike) with the day after a vigorous hike. It would also be interesting to repeat the above two measurements on days when you took aspirin (i.e., 1. hike, aspirin 2. hike no aspirin 3. no hike, aspirin 4. no hike, no aspirin).

[brachyrhynchos]

bibliophage - you've asked a question that I've been wondering about myself. If I am doing fieldwork and it's been a particularly long day, I get chills at the end of the day. It doesn't matter what the temperature of my environment is - I get home and about an hour later my body temperature drops. To counteract this, I take a very hot shower and this seems to help. The next day my body temperature is normal (so I don't have the increase you experince).

I don't think that aspirin plays too much into this. First, aspirin's effect on temperature regulation is to lower elevated temperatures, but not below normal body temperatures. If you have a normal body temperature, taking aspirin will not lower it. Second (and anecdotal), I don't normally take aspirin after working and I experience the body temp drop too.

I've wondered what causes this and since it is something that I have experienced more often as I grow older (I'm 44), I guess I've just attributed it to my body taking more energy to repair itself. I don't think I am as effective in repairing damaged (heavily used) tissue as I was 20 years ago. Perhaps I need to use more resources to make the same repairs my body did years ago. I wish a mammalian physiologist could give their input.

I think Yeah's suggestion of taking your temperature is a neat idea. If you do this, try to find some disposable thermometers and take some hourly temps. You could first assess how you feel ("On a scale of 1 to 5, how hot do I feel, with 3 being normal?") and then you could see if your body temperature correlates with personal assessment. Hmmm, since I'm doing some heavy fieldwork next week, maybe I'll give this a try.

[iampunha]

Possible explanation: you've probably got a fair bit of wetness/moisture/sweat on your skin. If it's cold, the water is going to take energy/heat from your body to evaporate, a process made more difficult by the fact that it's cold. The cold is going to literally suck out heat from your body.

When it's hot, said sweat/whatever isn't going to give up that much heat when it evaporates. Also, you tend to feel hot if it's hot no matter if you've just been exercising or you just came from a cold shower.

Just MO.

BTW, lack of electrolytes affects your homeostasis: your body's abolity to regulate things like temperature. If you can't regulate that, you're up shit creek without a warm winter coat.