In some cases we know the cause: e.g. microgravity leads to fluid shifting to the head, causing 'face bloating'
Spaceflight is an extreme environment that causes many negative health changes to the body
In other cases, the causes of the problem are not yet known: e.g. muscle loss in space
Muscle loss is important for spaceflight
Astronauts lose up to 40% of their muscle after 6 months in space
This muscle loss would reduce in-flight performance and threaten astronaut health on longer missions
Understanding the causes of muscle loss in space, and using this knowledge to find effective therapies, is therefore important for the future of space exploration