Astronautics Question:

A normal body will adapt to the abnormal environment of space in many ways. Immediately upon entering zero gravity, fluids in your legs and the lower part of your body move upwards towards your head. In fact, your face will feel and look swollen. Except for the occasional headache and congestion, astronauts are not bothered by this fluid shift. Some astronauts feel dizzy and have an upset stomach during the first few days of a space flight as they get used to zero gravity. This feeling usually goes away after three or four days. After a few days almost everyone is used to zero gravity and feels great. If you do not exercise, your bones and muscles will get weak.