Astronauts staying at the International Space Station are hardly able to work out their muscles as we can do on the Earth’s surface. This is because of the gravitational pull of Earth that we need to make more efforts to lift our body weight. However, the International Space Station has an environment of weightlessness where a person does not need to make much effort to propel forward. As it is very much required to exercise in order to keep our heart and muscles healthy, astronauts also need to work out to stay fit in space.
Another important reason for astronauts to keep working out on the International Space Station is to avoid facing a situation called osteoporosis. Due to bone loss, one could have this disease. While astronauts keep swimming in a weightless environment for a long time period, they experience the effects of microgravity and start losing their bone mineral density. Losing bone mineral density from various body parts is quite significant in space. To avoid a significant bone loss, astronauts need to stay healthy and fit even when they are living in a space environment.
In addition, they need to maintain their bone mineral density so their bones do not become weak. Weaker bones have more chances of fracturing on return to Earth. As their skeletons do not bear any weight in space, their bones do not remain that capable of forming fresh bone cells or replacing old cells. This leads to a slowed-down movement of essential minerals in their bodies.
To maintain at least some movement, all astronauts perform different kinds of exercises while they are on the International Space Station. Some of these exercises include working out on specially designed treadmills, mechanical bicycles and resistive exercise devices. They also perform weightlifting moves in space. All these workouts keep them stronger in a weightless environment.