Despite Exercise, Zero-G Makes Astronauts as Wimpy as 80-Year-Olds

By Eliza Strickland | April 9, 2009 1:48 pm

ISS exerciseAstronauts who live aboard the International Space Station for months are losing more muscle mass and strength than researchers thought, and NASA thinks there’s only one cure: a better workout. A new study that used MRI scans and biopsies to test astronauts’ muscles before and after a stay at the space station found that the volume of their calf muscles decreased by an average of 13 percent during six months in space…. [Lead researcher Scott] Trappe says that the magnitude of loss in muscle mass is akin to the difference between a 25-year-old and an 80-year-old [Scientific American]. Leg muscles are the most vulnerable to atrophy, researchers say, because on Earth they receive constant exercise just by supporting a person’s weight.

Space station residents currently exercise at least two hours each day to prevent their muscles and bones from wasting away in the weightless microgravity environment. The recent study showed a range of astronaut exercise regimens, including five hours per week spent on aerobics, and anywhere from three to six days per week spent on resistance training []. However, the treadmill and exercise bike that astronauts use are mostly intended to maintain cardiovascular health, and are little help for muscle strength.

Muscle strength is the responsibility of the Interim Resistance Exercise Device, or iRED — and, with a maximum resistance of just 300 pounds, it can’t do the job. “Astronauts are working out hard, but the loading characteristics aren’t there,” said Trappe. “They’re losing more muscle mass than they should be” [Wired].

Trappe’s study, published in the Journal of Applied Physiology, is further justification for the fancy new piece of exercise equipment that was installed on the space station in November: the Advanced Resistance Exercise Device (aRED). Smaller and more powerful than any earthly all-in-one gym set, aRED is expected to provide astronauts with much-needed muscle work. “When we think about the space environment, you have to reset the baseline,” said Scott Trappe, director of Ball State University’s Human Performance Laboratory. “On Earth, it’s hypertrophy: ‘How big can I get my muscles?’ In space, it’s ‘How can I protect what I have?'” [Wired]

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Image: NASA. Russian cosmonaut Oleg Kotov works out on the Interim Resistance Exercise Device

CATEGORIZED UNDER: Health & Medicine, Space

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