If your body temperature is 98.6 degrees, shouldn’t temperatures in the 90’s feel comfortable? Why do we run for air conditioning when in fact the air temperature is in harmony with our body temperature?
In layman’s terms (mainly because I remember hearing this discussed but don’t remember the specifics), it’s because A) Our bodies move and B) We wear clothes. So if we laid down, completely nude, and stopped all body functions, we’d be damn comfortable at 98.6 degrees. Or so goes the explanation.
Anyone knowledgeable on the subject should feel free to kick me repeatedly in the pants.
Body makes lots of heat.
Body loses heat because surrounding air cooler.
Surrounding air not cooler, body loses far less heat.
Ow. Hot, body. Hot. Eeeeeeeeee!
That’s probably the same reason why you’d have a tough time drinking a liquid heated to 98.6 degrees, too.
Could it be because we’re warm-blooded and have a need to cool our bodies through external means?
Don’t we do it all the time when we drink coffee or tea that has just been boiled?
Actually, coffee’s a lot hotter than that.
Your body has to maintain a temperature of 98.6 degrees, or 37 Celsius. To do that, it constantly creates heat. The amount of heat your body creates at a normal level of activity is MORE than it needs to maintain body temperature. The reason 66-72 degrees feel comfortable is because that’s the temperature at which your body, under normal circumstances, will lose about the right amount of heat to burn off the excess heat it’s producing. (This assumes you’re wearing an ordinary suit of clothes; if you were naked it’d be 75 or so.) We’ve evolved this way, making more heat than we need and letting it go into the atmosphere, because it gives us flexibility to deal with most of the temperature variations we’d encounter. That excess heat keeps you alive when it’s near freezing, and when the temperature goes up to 100, you can increase heat loss by sweating, reducing activity, and ingesting fluid.
So 98.6 feels hot because you can’t let your excess heat go. This ALSO explains why 70 degree water feels cold as hell, while 70 degree air is fine; the water drains heat from you very quickly compared to air. (Of course, that’s why we sweat.)
Of course, “comfortable temperature” varies from person to person. Slight differences in metabolism might mean you like the room at 68 where I like 70. Heavy people tend to like it cooler than thin people, since they lose heat slower (fat insulates.)
Humidity makes it even worse. A lot of places that reach 90 degrees or more also get quite a bit of humidity. The more water in the atmosphere, the harder it is for your sweat to evaporate. Last week when it was hitting 98 degrees here, it was a humidity of 80%. That makes it feel like 110. Walking outside was like walking into a hot, wet towel. The sweat has just nowhere to go.
I think a lot of it has to do with what the person is used to. I’m sure that people who live in climates where it never gets below 90 don’t think it’s uncomfortably warm when it’s 98, though they probably don’t even think about the fact that they are sweating. People from colder climates are uncomfortably warm in what our air-conditioned culture thinks of as comfortable.
Sorry Badtz, but I can vouch for the fact that being born and raised in the tropics is no defence against feeling uncomfortable once the temperature goes above about 35oC. The human body generates heat, and burns energy to remove excess heat. This makes anyone feel uncomfortable and lethargic. Being acclimatised seems to make it easier to function even when you don’t feel like it, but it’s not something that goes unnoticed. I think part of the problem is that even in the warmest parts of the tropics temperatures routinely drop to below 10oC on a winter’s night and the thermostat has to be set to cope with these lows as well as high temps.
I agree with the notion that it’s all about heat transfer. The body needs to get rid of a given quantity of heat per unit time. The ease with which this is done depends on:
[ol]
[li]The surface area available for heat exchange[/li][li]The efficiency of heat exchange with the surrounding medium[/li][li] The temperature gradient[/ol][/li]
Our perception of how warm or cool something is depends greatly on factor #2 above. Consider the case of water versus air at 90[sup]o[/sup]F. 90[sup]o[/sup] air feels quite warm (the body isn’t easily getting rid of excess heat) whereas water at this temperature is very comfortable-even a bit cool (because given an identical temperature differential, water is more efficient at conducting heat away from you).
For another example of the above, but with different materials, take the case of using a wood-handled versus metal-handled tool working outside, bare-handed on a cold winter’s day. The handles are the same temperature, but the metal one feels strikingly colder because it more efficiently conducts heat away from your skin.
Air at 80 is kinda hot but if you are in water that is 80, it’s just kinda nice.
No doubt you are familiar with the phrase “piss warm”?
We prefer our beverages either hotter or colder than body temperature. The only thing I can think of that is deliberately drunk at body temp is brandy.