Exercising in Space
Why is Exercise Important in Space?
Exercising in space is not just for fun; it is necessary to keep astronauts healthy and functional. On Earth, gravity works against our muscles and bones every time we move. This requires our bodies to maintain enough muscle and bone mass to support our own weight. In the weightless environment of space, where the relative force of gravity is minute, astronauts lose muscle mass and bone density since it is not required to support their weight.
Exercising in space is the most effective way to date to compensate for the relative lack of gravity. However, even with rigorous exercise, astronauts have typically lost up to 0.4-1% of their bone density per month in space. Although astronauts gradually recover their muscle tissue and most of their bone mass when they return to Earth, it is important that they are strong enough to perform strenuous activities in space, such as spacewalks, and emergency procedures during landing. Completing a regular exercise routine in space prepares the astronaut for these situations and also facilitates a shorter period of reconditioning to recover their muscle and bone.
A recent study has shown that the International Space Station (ISS) astronauts who use the Advanced Resistive Exercise Device (ARED) daily, eat sufficient calories and have adequate vitamin D during a four to six month mission are able to maintain bone in most regions of their body. In addition, although astronauts return to Earth with the same body weight, they have a lower percentage of fat mass and a higher percentage of muscle mass. Researchers are now investigating if the strength of astronauts' bones post-flight is as good as before their flight.
How Often do Astronauts Exercise in Space?
Astronauts who live on the ISS for periods up to 6 months are required to exercise for approximately two hours per day. Each astronaut's exercise routine is monitored, and can be adjusted if necessary based on his or her monthly fitness assessment and data from daily exercise sessions. If astronauts are scheduled to perform a spacewalk, their exercise routines may be altered or restricted.
ISS crewmembers use a cycle ergometer for cardiovascular exercise, a treadmill for cardiovascular exercise, loading the skeletal system and maintaining the neuromuscular patterns for locomotion, and a Resistance Exercise Device for maintaining muscles and bones.
The exercise equipment operates with vibration isolation systems to prevent the forces created by the astronauts working out on the equipment from disturbing scientific experiments.
Did you know?
NASA astronaut Sunita Williams completed the first triathlon from space on September 16, 2012
CSA Astronaut and ISS Commander Chris Hadfield shares his workout routine with us. Credit: CSA/NASA
- Date modified: