Real world Why exercise is essential
On Earth, gravity loads our bones and muscles every time we stand or walk. In weightlessness, that load disappears. Astronauts can lose bone density in their hips and legs, often around one percent or more per month, and muscles weaken. Their hearts and blood vessels also adapt in ways that can make them dizzy when they return.
Real world The space station gym
Astronauts on the International Space Station exercise for about two hours a day. They run on a treadmill while wearing a harness that pulls them down, pedal a cycle without a seat, and lift "weights" on a machine called ARED, which uses vacuum cylinders to create resistance because ordinary weights would float.
Possible future On the Moon and Mars
The Moon has about one sixth of Earth's gravity and Mars about three eighths. Nobody yet knows whether that is enough to keep people healthy over years. A settlement gym would combine exercise machines with medical tests to track bone, muscle and heart health, and research would watch residents closely.
Art In this artwork
This illustration shows a gym building with a glowing exercise chamber and machinery.
Look closer
- Find the glowing exercise chamber.
- What equipment might be inside?
Think about it
- How would you stay fit if you could not walk normally?
- Why might exercise be more important in space than on Earth?
- How much exercise do you get each day?
Key words
- Bone density
- How solid and strong bones are.
- Countermeasure
- Something done to prevent a harmful effect.
- Resistance exercise
- Exercise that works muscles against a force.
Use it in class
- How do astronauts live on the International Space Station? (Explainer, grades 3-12)
Sources
The real-world facts on this page are based on these sources:
- NASA, exercise on the International Space Station (treadmill, cycle and ARED)
- NASA Human Research Program, hazards of human spaceflight (radiation, isolation, distance, gravity, hostile environments)
