Almost everyone has dreamed of being an astronaut at some point in his or her life. After all, it’s a fun job, right? Astronauts get to fly around in their spaceships, floating with no effort, accomplishing amazing missions. Definitely all fun and games.
Well, wrong. Weightlessness may look like a lot of fun, and I’m sure it is, but being weightless for a long time isn’t good for your body. In fact, no-gravity can be so harmful that astronauts returning to Earth have difficulty even walking because their bodies have adjusted to moving around without much effort!
Basically, micro gravity (when there is very little or no gravity, as in space) hurts the human body in two main areas: muscles and bones. When you are weightless, everything is easy. Your muscles don’t have to work to support your body weight, to help you walk or to keep you in balance. Without the force of gravity to work against, muscles take a vacation. They wither away or atrophy under weightless conditions.
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To try and avoid muscle loss, astronauts exercise vigorously. They use special exercise equipment which forces the muscles to work. This seems to be an effective way to prevent muscle loss, but weightlessness still remains a problem for human bones. Weightlessness for long time periods makes the bones loose calcium. The entire skeleton tends to weaken because of demineralization (a loss of minerals and vitamins). The cause of this loss isn’t really known, but scientists believe it occurs because the bones don’t have as much pressure placed on them in zero gravity environments. Like the muscles, when your skeleton goes without being ‘exercised’ or used to support the weight of your body, the bones waste away. Now that you know what astronauts who stay in space for a long time have to put up with, you may look at them differently.
