HUMAN NUTRITION

Detailed explanation-1: -In the absence of gravity there is no weight load on the back and leg muscles, so they begin to weaken and shrink. In some muscles degeneration is rapid, and without regular exercise astronauts may lose up to 20 percent of their muscle mass within 5-11 days.

Detailed explanation-2: -Thanks to the current protocol of two hours of exercise per day, astronauts return to Earth with more muscle mass than when they blasted off!

Detailed explanation-3: -They will exercise approximately two hours every day using exercise machines, such as treadmills and ergometers. The treadmill is a machine on which, the astronauts do running exercises with their bodies strapped to it.

Detailed explanation-4: -Why is it so important for astronauts to exercise while they’re in space? If astronauts don’t exercise, their bodies start losing bone and muscle. Bone and muscle loss mean decreased size and strength, and can reduce an astronaut’s ability to do work because it makes them weak.