HOW TO DO IT: Start with your left leg forward and your right leg back. Place your left foot onto one end of a towel and grab the other end in your right hand. Pull the towel as hard as you can without holding your breath. Hold for 30 to 60 seconds, then switch sides and repeat. If you can’t maintain the hold continuously, break it up into shorter five- to 10-second bursts with brief one- or two-second rests in between.

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.