For those sticklers who object to this regimen as a violation of the no-equipment stipulation—what are you, trapped in a shipping container?—Okafor has a go-to airport circuit, too, no chair required: four rounds of 20 squats, 20 lunges (with each leg), and 30 bicycle crunches. Maybe you're thinking: the airport? But don't people give you weird looks? "Of course," Okafor says. "But they're usually out of shape." Spoken like a man who isn't one bit afraid to curl a chair with a towel.
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.