Studying the effects of microgravity on the human body
Sen— Living in microgravity has many consequences for the human body. Bone deterioration and muscle loss mean crew members aboard the International Space Station must excercise for 2 to 3 hours every day. Fluid redistribution triggers the body to excrete fluids, leading to dehydration. Decreased physical stress causes the heart to slow down and reduces the production of red cells causing "space anemia". Immune system and production of infection fighting cells is reduced. Prolonged weightlessness also causes blurred vision after about 6 weeks that can perist for months after returning to Earth. Balance is also impaired as inner ear receptors are affected, with returning astronauts often experiencing dizziness. More minor problems include puffiness of the face, flatulence, weight loss, nasal congestion, sleeplessness and space sickness as the body tries to adapt to being weightless.