Everyone knows that it’s important to exercise to stay in shape—on Earth, that is. But when you’re in orbit, exercise is absolutely vital!

Physical activity is the most effective way to counteract the adverse effects of weightlessness on the human body. Exercise is therefore a crucial part of the daily routine on board the International Space Station (ISS). Over the course of a long-duration mission, astronauts must exercise approximately two hours per day!

On Earth, each time we move, gravity provides resistance to the muscles and bones of our body. It’s like we’re exercising without even realizing it! That way, our body stays strong enough to support our weight.

In microgravity, however, bones and muscles no longer have to support the weight of astronauts’ bodies. What’s more, the cardiovascular system becomes lazy because the heart doesn’t have to work as hard as it does on Earth to counteract gravity and pump blood up to the head.

If astronauts didn’t exercise while they were in space, their bodies would experience major loss in muscle mass and bone density.

Read more and watch videos of astronauts working out in this report from Canada’s Space Agency.

Filed under: Special Features

Tags: astronaut physical fitness, International Space Station, muscle mass, Space, zero gravity effects on human body