Most competitive bodybuilders spend hours trying to do many sets over and over again. You don't need to do that. Various studies show that you can gain up to 80 percent of your maximum strength by picking out four to eight specific lifts, lifting one set of ten of the heaviest weight in each, and repeating your program two or three times a week.
Athletes and other very fit people may feel dizzy when they rise from lying to standing because of their slow pulse rates. Exercise makes your heart stronger so it can pump more blood with each beat and it doesn't have to beat as often.
You are supposed to exercise. It makes you stronger, faster, healthier and may even prolong your life. However, every time you exercise, you risk injury and many sports injuries last forever. Depression, heart attacks, strokes, obesity and diabetes are all associated with a sedentary lifestyle. A twisted ankle can change an active person into a sedentary one. A torn anterior cruciate ligament or meniscus of the knee has a greater than 50 percent chance of causing permanent pain within five years, regardless of the treatment.
Good treadmills have a lever that raises the front end to simulate running up hills, because running on level ground does not do much to strengthen your upper leg muscles. Running strengthens primarily your lower leg muscles.