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Living in Space

Exercising in Space

NASA Astronaut Edward T. Lu, Expedition 7 NASA ISS science officer and flight engineer, exercises on the Cycle Ergometer with Vibration Isolation System (CEVIS) on the International Space Station (ISS). Image courtesy of NASA.

Cosmonaut Gennady I. Padalka, Expedition 9 commander representing Russia’s Federal Space Agency, exercises on the Cycle Ergometer with Vibration Isolation System in the Destiny laboratory of the International Space Station. May 20, 2004. (Image: NASA)

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. The longer an astronaut is in microgravity, the greater the loss.

Exercising in space is the most effective way to date to compensate for the relative lack of gravity. However, even with rigorous exercise, astronauts typically lose 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 emergency procedures during landing. Completing a regular exercise routine in space prepares the astronaut for these situations and also facilitates a shorter period of rehabilitation to recover their muscle and bone.

NASA Astronaut Don Pettit, Expedition Six NASA ISS science officer, exercises on the Treadmill Vibration Isolation System (TVIS) using a subject-loading device (SLD) on the International Space Station (ISS). Image courtesy of NASA.

CSA Astronaut Bob Thirsk, Expedition 20/21 flight engineer, exercises on the Treadmill Vibration Isolation System in the Zvezda Service Module on the International Space Station. Note the subject-loading device around his shoulders and chest securing him to the treadmill. Nov. 11, 2009. (Image: NASA)

NASA Astronaut Edward T. Lu, Expedition 7 NASA ISS science officer and flight engineer, wearing squat harness pads, performs knee-bends using the Interim Resistive Exercise Device (IRED) equipment on the International Space Station (ISS). Image courtesy of NASA.

NASA astronaut Sunita L. Williams, Expedition 15 flight engineer, dons squat harness pads in preparation to exercise using the Interim Resistive Exercise Device equipment in the Unity node of the International Space Station. The IRED is currently in storage, replaced by the more sophisticated ARED. May 6, 2007. (Image: NASA)

How Often do Astronauts Exercise in Space?

Astronauts participating in space shuttle missions, which are usually two weeks long, exercise for approximately 30 minutes per day. Astronauts who live on the International Space Station (ISS) for much longer periods of time 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. If astronauts are scheduled to perform a spacewalk, their exercise routines may be altered or restricted.

Exercise Equipment

ISS crewmembers use a cycle ergometer and a treadmill for cardiovascular exercise, and a Resistance Exercise Device for muscle strengthening.

Cycle Ergometer

The cycle ergometer is similar to a stationary bicycle. The astronaut uses clip pedals and has the option of waist straps, back supports, and hand holds to secure themselves to the machine.
Treadmill

The treadmill requires a subject-loading device to secure the astronaut to the treadmill. The device consists of two spring-loaded cords that come from either side of the treadmill, which attaches to a harness around the astronaut's waist. The cords can be loaded with 66 per cent to 100 per cent of the subject's body weight to determine the strength of the workout.
Resistance Exercise Device (RED)

The RED consists of a pair of canisters attached to a pulley system and harness to mimic weightlifting on Earth. Astronauts can perform heel lifts, squats and deadlifts to strengthen the muscles that do not get much use in space.

Both the cycle ergometer and the treadmill operate with a vibration isolation system to prevent the forces created by the astronauts working out on the equipment from disturbing scientific experiments.

Advanced Resistive Exercise Device (ARED)

The ARED employs vacuum cylinders to create muscle resistance for the user. This mimics weightlifting on Earth. Astronauts can perform heel lifts, squats, deadlifts, and other exercises, to strengthen the muscles that do not get much use in space. ARED is an update to IRED, which consists of a pair of canisters attached to a pulley system (rather than vacuum cylinders) and a harness to create muscle resistance. IRED is currently stowed aboard the ISS and available for contingency purposes.

Canadian Astronaut Bob Thirsk talks about the Advanced Resistive Exercise Device (ARED)

CSA Astronaut Bob Thirsk demonstrates the Advanced Resistive Exercise Device (ARED)
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