Start by placing a chair on a sturdy surface against a wall with the seat facing towards you. You can also do tricep dips on the edge of a staircase (such as the 2nd or 3rd step from the bottom) or a workout bench. Stand 1 to 2 feet (0.30 to 0.61 m) in front of the edge of the seat of the chair. Place your hands behind you, shoulder width apart with your fingers gripping the edge of the chair. Bend your knees so they are at a 90-degree angle and your knees are directly above your ankles.
McAlpine's favorite on-the-go exercise is a classic for a reason: Push-ups are one of the most effective bodyweight exercises around. "Primarily, this move will target your chest, triceps, and your anterior deltoid muscles (the front of your shoulders)," says McAlpine. It also seriously works your core. Plus, there's something that just feels badass about working on push-ups and seeing yourself improve over time. "I personally love that feeling of strength that comes from this simple move," says McAlpine.
Exercise has long been correlated with a longer life, but it’s only recently started to become clear why this might be. Studies, like a new one in the journal Preventive Medicine which found that exercise is linked to longer caps at the ends of chromosomes, have helped flesh this out a bit more. These caps, called telomeres, naturally shorten as we age, with each cell division. People who live a long time have telomeres that are in better shape than those who don’t—but there’s a lot we can do to affect the rate at which they shorten over the years. The team behind the new study looked at data from CDC's National Health and Nutrition Examination Survey, and found that for people who exercised regularly, their telomeres were 140 base pairs longer on average than sedentary people's. Which correlates to being years “younger” than their sedentary peers.
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.