How do astronauts stay healthy in space?

Updated November 22, 2016

Space travel provides unique health challenges. Astronauts must protect themselves from X-rays and other radiation, keep clean while in space, and exercise their bodies to combat the effects of weightlessness. In some ways, astronauts face the same health concerns that people on Earth do but at an accelerated rate; other health concerns are unique to travel through space.

Protection from Radiation

On Earth, people are somewhat protected from ultraviolet radiation by the atmosphere. Sunlight is filtered through the ozone layer before reaching our skin; while we still have to protect ourselves from sunburn and skin cancer, the risk is not as great. In space, there is no atmosphere to protect astronauts from ultraviolet or other radiation. Astronauts wear heavy spacesuits when outside their vehicle to compensate for this problem. Space suits shield them not only from ultraviolet rays but from gamma rays and cosmic rays that can interfere with their DNA as well as their skin. In addition, NASA crew members monitor the radiation on space stations to make sure astronauts are not taking unnecessary risks.

Muscle Strengthening Exercises

If you don't exercise your muscles, they begin to atrophy, or get weaker. This is doubly true in space, where the astronauts are weightless. The lack of gravity pulling against the astronaut's muscles or objects she is carrying makes it easier to move or carry things, but it also means the muscles don't have to work as hard to accomplish tasks as they do on Earth. For this reason, the astronaut's muscles are at greater risk of atrophying. To combat this problem, astronauts must exercise for two hours every day. They use special exercise equipment that is designed for use in space.

Protecting Bone Mass

Exercise not only strengthens muscles, but strengthens bones. On Earth, people over the age of 50 tend to lose about 10 per cent of their bone mass over a period of 10 years. In space, bone mass loss occurs at an extremely accelerated rate: 1 to 2 per cent every month, regardless of the astronaut's age. Astronauts combat this with exercise that simulates jogging or running and by eating calcium-rich foods while in space.


Hygiene is as important in space as it is on Earth. If astronauts do not clean their bodies regularly, they become susceptible to germs. It would be difficult to take a shower in space because of the lack of gravity. Astronauts take a sponge bath every day, using one washcloth for washing and one for rinsing, and wash their hair with rinseless shampoo.

Getting Adequate Rest

On both Earth and in space, people need enough sleep every night in order to ward off disease and think clearly. Astronauts cannot sleep in beds like we do on Earth; instead they strap themselves into sleeping bags. Astronauts try to get eight hours of sleep every night that they are in space so that they can be alert and avoid danger.

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About the Author

Jack Ori has been a writer since 2009. He has worked with clients in the legal, financial and nonprofit industries, as well as contributed self-help articles to various publications.