Quirks & Quarks

If fish don't experience gravity, can astronauts learn from them to stay in shape?

Fish don't work against gravity, they work against the resistance of water. Could this be a model for astronaut workouts in space?

Fish don't work against gravity, they work against the resistance of water

The resistance fish experience from continually pushing against water could help astronauts aboard the ISS maintain their muscles while onboard the ISS (Annette Shaff / Shutterstock)

This week's question comes from Bill Dales in Port Coquitlam, British Columbia. He asks:

In space, muscle weakness is a problem because of the loss of gravity. Efforts are made to replace gravity with exercise but so far without success. Fish live in a low gravity environment and yet they have muscle strength. Can we duplicate what fish do to stay strong? Instead of attempting to replicate gravity can we replicate what fish do in nature?

Emily Standen, an associate professor of evolutionary and comparative biomechanics at the University of Ottawa, says that fish in water are swimming in an environment in which gravity does not provide resistance to motion. However, they are constantly pushing against the fluid around them.

This provides a force for their muscles to work against as water is more dense than air for example. In other words, fish are continually working out. 

Hypothetically, filling the International Space Station with water would therefore be a good way for astronauts to keep muscle strength, having a similar force to push against as fish.  Breathing, however, would be an issue.

Standen suggested it might be interesting to develop an astronaut suit made of an elastic material, that would resist their movements in a similar way to moving in water, as they move around the Space Station. 





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