Especially you young men. When was the last time you were physically uncomfortable? Challenged yourself? We have uncomfortable times ahead, but it's possible to condition your personal comfort level, to increase tolerances. For example: I grew up without AC, and have never habitually used it as a part of my lifestyle. My comfortable temperature for sleeping is in the low 80's, before I need a fan on me. (My mother doesn't visit. lol) Try hiking 20 miles, spending the night outdoors, then hike 20 miles home. Try going 2 days with no food. Try no electronic entertainment for 2 days. Try something.