As people enter their forties and fifties, muscle mass starts to decline because of aging and, in some cases, decreased activity levels. Muscular atrophy can also occur because of health conditions, such as joint pain. As we age, it’s important to increase or maintain muscle mass through strength training, not only because it helps burn calories, but also because muscle mass is essential for strength and balance.
What you can do is remove body fat from your entire body. Basically, you have to decrease your overall body fat composition if you want to lose weight from any specific place on your body. When you do that, you are going to eventually target the part of your body you want and you're going to lose body fat there. You can't just do 1000 push-ups every day and lose arm fat. Instead, you have to lose body fat in your entire body while building those arm muscles. You build up those muscles so that when your body fat percentage is low enough, they can show through.
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.