If you want to be an astronaut, it's important to be in good physical condition...

What kind of exercises do you do in space?
-- Myra (Team Spirit)

MAGNUS: It is very important that we exercise regularly and they schedule us for 2 hours a day. Part of it is cardio, which we do on either a treadmill or a stationary bike, and part of the exercise is kind of like weight lifting (but we use resistive devices to simulate the "weight") so that we can load our bones and muscles. Without doing exercise, our bones and muscles, especially those in our lower body, start to atrophy and weaken and we cannot readapt to life in the gravity of Earth very well. Also, the exercise helps us maintain our bone density so our bones do not get brittle.