I served in America’s last cold weather battalion at the very end of the cold war era in 1991. During that time we still trained in Norway. It was 250 miles north of the arctic circle and it was very cold to say the least. In order to maintain our body weight we were required to eat 4000 calories per day. If we at less than 4000 calories per day we would begin to lose weight because our bodies were burning so many calories in an attempt to maintain core body temperature.
At the time I didn’t realize that the concept of thermal load was something that could be used to aid in weight loss. It was only after reading The 4 hour body by Timothy Ferris that I began to realize just how useful thermal load could be to anyone trying to lose weight. When your body is surrounded by cool or cold water your body must burn extra calories above and beyond the calories being burned off by the act of swimming. Your body must also burn calories (at the same time)