Why can a trained athlete run a marathon, but a couch potato cannot run half a mile?
If you are out of shape, you know it. Even climbing a flight of stairs can leave you out of breath! If you haven’t been exercising regularly, even a little exercise, like going up steps, can put a strain on your body. Your body responds to exercise with a coordinated effort from many systems, including working muscles, the heart, lungs, blood vessels, skin, brain and others. Here are what the different parts of your body do when you exercise: • The muscles provide the strength, power, and endurance to do the exercise. • Enzymes within the muscles mobilize various fuels to provide ATP to meet the energy demands of working muscle. • The heart and blood vessels increase the
