Hello all. First-time poster, looking for some help settling a disagreement.
These are the facts:
Two otherwise absolutely identical individuals (down to the last atom) are sitting in a house together all day long, with an ambient temperature of say, 68 degrees F. One person has been wearing a sweater all day. These two individuals then decide to go see a movie, so as they approach the front door, the individual not wearing a sweater puts on a sweater absolutely identical to the one being worn by his clone. At the moment they step outside together (where it is 30 degrees F.) , these two identical individuals are therefore wearing identical clothing. Barring any negligible differences, would either individual “become cold” (have a lower body temperature – core or at the surface) faster than the other? Would either be more likely to become ill? Alternatively, would perception of how cold it was outside be the only difference?
Thank you in advance. Eagerly awaiting your replies.
How do you feel about goats?
Second–becoming cold has to do with losing heat. Both people are physically the same, & garbed the same, in the same temperature. So, they lose heat at the same rate.
Well, the fellow who was wearing the sweater all along has a layer of warm air trapped around him and the fellow who just suited up doesn’t.
I dunno how long it’d take for that difference to equal out but I think that for a little while at least the one who was already wearing a sweater would feel warmer and wouldn’t lose body heat as fast.
Twin1 was wearing the sweater.
Twin2 puts on the sweater.
Are we ignoring the impact the insulation has on homeostasis?
Because Twin2 had less insulation, he would be losing more body heat in the 68F house, and so would have a higher heat production rate to compensate and maintain body temperature.
So, Twin2 is producing more heat than Twin1.
If you have two equally insulated bodies, the one producing more heat will end up warmer.
How it plays out, though, depends on how fast the body responds to environmental changes to control body temperature, where body temperature is actually measured for control purposes, and where body temperature is sensed for the comfort response.
I’d think Twin2 might overheat, then lower heat production and start sweating, cool off too much and then ramp up heat production… and basically oscillate back and forth until homoeostasis was achieved again.
Twin1 would do the same thing, but the initial upswing would be less drastic.
So Twin1 would probably be more comfortable over the course of the test.
Er, I think Twin1 (the one who’s had the sweater on all day) would stay warmer than Twin2 because Twin1 has been preserving body heat for a longer period of time than Twin2. But, like Ravenman said, they probably won’t get colds, but Twin2 will probably feel colder than Twin1 when they go outside.
OTOH;
My SWAG would be that twin2 (no sweater) would feel warmer, at least initially.
When your body loses heat faster than it produces it, you feel cold. Since twin1 had additional insulation in the house, s/he would have been losing less heat than twin2, thus producing less heat internally to maintain his/her core temperature. Once they stepped outside, their insulation and rate of heat loss will be the same. Since twin1 has an initially lower rate of heat production, s/he will have a greater sensation of cold as s/he will have a lower net heat (Heat produced - Heat lost).
Another factor which may affect heat loss is that twin1 will likely have a higher skin temperature due to the insulation of the sweater in the house. Heat transfer is directly related to temperature difference and therefore twin1 will (initially) have a higher rate of heat loss, qed, feel colder.
(Now I wait for QED to come along and correct me.)
Here’s a bit of trivia from my scouting days that might answer the question, although in a way that’s at odds with everybody else’s answer:
When you’re cold-weather camping in a sleeping bag, you can (a)sleep in your underwear and put your clothes on after you get out of the sack, or (b) sleep with your clothes on and emerge fully dressed. We were always strongly advised to do (a), because you’d lose more heat if you did (b). Of course, I have no living cite for this beyond the fact that I have not yet died from exposure–though I haven’t been cold-weather camping in nearly 30 years.
My experience on camping trips with my father was much the same as Krokodil. Always sleep as close to buck-naked as you comfortably can in your sleeping bag and then dress when rising. In fact, Dad carried it a step further. While hanging around camp, and the camp fire, you didn’t get fully dressed; just pants, shirt and boots. You waited to put on your coat until you were leaving the fireside. Worked for us. Dad was in the Army in WWII (Germany), don’t know if that is where this way of doing things came from or not.
Twin1 wears the sweater in doors.
Twin2 puts on the sweater just before going out.
Twin1 will initially have warmer air inside the sweater (warmer than room temperature). However, Twin1’s sweater will be damper, because Twin1 will sweat into the sweater while he is wearing it indoors! Twin1’s exposed skin will be wetter, as Twin1 has been sweating more, indoors (even if not visibly sweating). Depending on many factors, Twin1 may be immediately chilled by the evaporation when he steps into the outside air.
I WAG that the humidity of the sweater is more important than the temperature of the air inside the sweater. Air temperature changes more easily than humidity, right? The humidity of the sweater could have a cooling effect long after a dry sweater would reach temperature equilibrium.
The situation that you described was explained to me (also in Scouts) that if you sleep in your clothes you’ll get chilled because of the sweat that is trapped in there. When you don’t sleep in your clothes they have a chance to dry out. Dry body = warmer. Of course, if your clothes are out in the tent then they’re going to be c-c-c-old in the morning. I like to keep fresh, dry clothes in the bottom of my sleeping bag, then slip them on before I pop out of it. 'Course I’m a total wuss when it comes to cold.
