This workout incorporates three blocks that you will rotate through four times. The first round is the longest (I told you I always like to get the hardest part of the workout done first!) and the duration of each subsequent round decreases a bit. Hopefully this serves as motivation to stick with it, knowing you’ll knock out the hardest part of the workout first!
The skin also serves as a release point for heat. (See “Why Does My Face Turn Red When I Exercise?” for more on that.) When you exercise, your muscles generate a lot of heat, which you have to give up to the environment so your body temperature doesn’t get too high, Hackney says. The heat in the muscle transfers to the blood, which shuttles it to the skin; it can then escape into the atmosphere. 
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