What happens to muscle and bones in space?

Muscles

In space, astronauts experience microgravity, which means that they are in a state of free fall and do not experience the same forces of gravity that they do on Earth. This lack of gravity can cause muscles to atrophy, or waste away, because they are not being used as much as they are on Earth. Astronauts can lose up to 20% of their muscle mass during a six-month mission in space.

To combat muscle atrophy, astronauts must exercise regularly while in space. They use a variety of exercise equipment, including treadmills, stationary bicycles, and resistance bands. They also perform resistance exercises using their own body weight.

Bones

Bones also experience the effects of microgravity in space. In the absence of gravity, bones do not have to work as hard to support the body's weight, and they can begin to lose density. This condition, known as osteoporosis, can lead to weak and brittle bones that are more likely to fracture.

To prevent osteoporosis, astronauts must take supplements of calcium and vitamin D, and they must exercise regularly. They also use a special suit called the "G-suit" that helps to keep blood flowing to the lower extremities and reduces the effects of microgravity on the bones.

Despite these measures, astronauts still experience some muscle and bone loss during their time in space. However, by exercising regularly and taking supplements, they can minimize these effects and maintain their health.