As anyone who has experienced middle age will know, the process of growing old can be extremely hard on the body. Your bones begin to leak calcium, your muscles begin to shrivel, the immune system weakens, and arthritis can set in. Poor posture and balance affect how you move about the world, while cataracts and deteriorating eyesight impair how you see it. Heart problems and declining cognitive function eventually set in as people approach the end of their lives.

These symptoms, however, can also be caused by something less common: space travel.

Spaceflight influences biology in dramatic ways, and people in space appear to experience the effects of aging faster than people