Asked by Jay Davies
Humans are adapted for life on Earth and therefore experience many different, and generally adverse, effects on their body from the long-term weightlessness of spaceflight.
One of the main problems that an astronaut suffers from is a loss of muscle and bone mass – a reason why astronauts must undertake around two to three hours of exercise every day. In the weightless environment astronauts also experience motion sickness and balance disorders, nasal congestion, disruption of vision and a weakening of the immune system.
Spaceflight can affect people differently, though, and some astronauts experience certain symptoms more than others. There is still much more to learn and so further investigations into the effects of spaceflight on the human body are constantly taking place on the International Space Station.
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