When/what is the best way to use thermal underwear?

Question

My girlfriend says that once the weather starts getting chilly, you should start wearing them, and you shouldn't take them off until summer because your body temperature adjusts to them and you will catch cold. She says there are long johns made in different weights for the different seasons, fall, winter, and spring. I say she's nuts, that the reason they're made in different weights is because people who work outdoors naturally need heavier ones than people who are just going to be out for a short time. I believe that it's just an old wives' tale that once you start wearing them you'll get sick if you take them off before summer. Who is right?

Answer 1

Thermal underwear is made for warmth. wearing them constantly or intermittedly will have no effect on your getting or not getting a cols. Colds are viruses and do not come from being cold. There are different weights, for different activities and temperatures. It is often uncomfortable to wear thermal underwear inside a heated building.

Answer 2

You are right.
I will wear them when I am going to be outside doing a winter activity etc.. but I will not where them all winter thats just silly

Answer 3

You only wear them in very cold temps. You are the right one.