Long period of weightiness in outer space, astronauts need to pay attention to the entertainment and exercise to stay healthy. In order to avoid having saggy muscle for being in the weightlessness for a long period, astronauts need to have weight training. Due to weightlessness, sit up and weight lifting become useless exercises. They should also avoid all the exercises associated with "force" such as jogging, boxing, and throwing. Otherwise, resistance will affect the safety of space shuttles.

Thus, doing exercises is quite limited in the space. Figure bellow shows the weight training situation of astronauts. What are other exercises? Do you have any idea?

After exercise, astronauts cannot take a shower like we do on the ground. They can only clean themselves with sponges or towel same as wash hair. Other difficult tasks include "going to the toilet." Astronauts need to sit on the well designed bowel and fixen themselves. After finishing, they cannot flush with water instead they need to use a special air vacuum to clean up, dehydrate and sterilized. Urine is also put in the container and brought back to the earth for treatment.