You sweat more after you finish exercising than you do while you exercise. More than 70 percent of the energy that powers your muscles is lost as heat, causing your body temperature to rise during exercise. To keep your body temperature from rising too high, your heart pumps the heat in your blood from your muscles to your skin
If you want to become very strong, you have to lift weights heavy enough to make your muscles burn. It doesn't make any difference whether you move the weights slowly or rapidly. Just exercise intensely enough so your muscles feel sore the next day.
Many exercise programs and tests used to measure heart function are based on an unreliable MAXIMUM HEART RATE formula that predicts the fastest your heart can beat and still pump blood through your body. Although this formula is the golden standard used today, it is not based on science.