On Earth, some people like to exercise more than others. Aboard the Space Shuttle, astronauts have little choice. On earlier missions, scientists discovered that astronauts suffered some bone and muscle deterioration because their bodies were not getting the resistance they were used to in gravity. Today, astronauts participate in a planned exercise program to counteract the effects of a near weightless environment. Exercising also helps people readjust more quickly to Earth's gravity when they return home.
Astronauts can use a treadmill as a form of resistance exercise.
The treadmill is a Teflon-coated aluminum sheet on a roller, with a bottom that locks into holes in the floor. Straps from the base of the treadmill tie around the waist. Astronauts exercise their arms by pushing upward on the bar while walking. Moving air from a nearby duct is used to dry off the perspiration produced from exercising. Otherwise, the sweat would stick to the skin and grow thicker and thicker.