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
  • Nick

    Why don’t they just butt-weld a bowflex-like apparatus into a human-shaped articulated frame and have them do chores strapped into it?

  • Jumblepudding

    what if they incorporated strong elastic resistance bands into the Atronauts’ daily wear , so the legs, for instance, are under constant tension when extended, like standing on Earth? It would look futuristic, what with the ribbing all over the outfit, and maybe it could take off in the earthbound sector as well.

  • Rabiah

    Given the negative effects of micro-gravity on bone density that earlier NASA studies have shown, this is a double-whammy for astronauts and space travelers. I wonder if a more simple solution is viable – train at high intensity before launch, building up muscle like a bodybuilder does while training for competition. Save for problems like having to alter the spacesuits in size, the in-space loss of muscle mass could return the astronaut to near-normal levels by the end of the trip. Is there any evidence that the bulky-to-normal transition (or repeated cycles of this) are particularly harmful? Seems like most of us do this anyway, during repeated love/hate relationships with the gym….

  • Brian M

    They should probably discontinue all aerobic exercise in favor of high resistance work. Who cares about cardiovascular health for the few months in space? It’s muscle mass and bone mass that will count for those short stints. Rabiah — not a bad idea bulking up pre-liftoff but I think demineralization would happen at same pace as bone density wouldn’t increase as much or as rapidly as muscle mass during the bulking up phase. I like some variation of Nick and Jumblepudding ideas that would in a sense mimic gravity. Combined with a stepped up resistance training regimen.

  • Jumblepudding

    I thought I was on to something with my idea, but alas, a band resistance suit is already patented for swimmers. I still say NASA should have a look.

  • Mr. Gently

    that’s not a viable option unless you want the astronauts using steroids and such.
    An adult man can not grow even 5 kg of pure muscle in a year, without cheating.

    I hope you do realize that every single top body builder is basically a cheater.

  • Rabiah

    Brian, good point, and Gently, yours is one I’ve considered, but I’m not one for sweeping generalizations. I’m by no means a professional athlete, but I’ve learned enough as a recreational triathlete/runner to know that the 12lb rule is not a hard-and-fast one. Besides, short-term ISS residents likely wouldn’t need prolonged preparation anyway.

    I am liking the resistance idea as well:-)

  • Jumblepudding

    Human growth hormone might be a valid option instead of steroids to make stronger astronauts. The risks can’t be that much greater compounded with getting shot into space and staying in a zero-G environment for months. Let the media get their panties in a bundle accusing NASA of doping our astronauts. They’re not competing, they’re doing work and research that can’t be done anywhere on Earth.

  • casey

    “They should probably discontinue all aerobic exercise in favor of high resistance work. Who cares about cardiovascular health for the few months in space?”

    The heart is a muscle too.

  • ken russell

    Recent research focused on muscle synthesis has indicated that amino acid
    uptake is coincident with the presence of insulin, glucose,
    luceine, and heavy resistance. My diabetes intervention process seems to
    facilitate dramatic improvement in the ability to grow new muscles
    in diabetic humans. This process may be of benefit to humans
    that are losing muscle mass in weightless environments.

    I am a 59 year old recovered diabetic on no medication or
    insulin. I weigh 170 pounds and I am 6’1″ tall.

    About seven months ago I got on a smith machine and set
    the bar with 230 pounds at six inches below full extension.
    I was able to perform 32 reps in three sets in about 10 minutes.
    I had never before attempted a weight of more than 125 pounds
    and that was five years before.

    Over the next 11 weeks I was able to add 10 pounds, each week,
    with only one 10 minute workout, to the highest weight of the previous week
    until I reached 340 pounds. I had not adjusted the height of the bar from
    the six inches below full extension. With the 340 pounds on the bar my
    shoulders were literally bent around the bench so that my full extension
    only raised the bar about 1.5 inches.

    This performance enhancement was attributable to the “two a day”
    applications of my diabetes treatment process and the tremendous
    increase in amino acid uptake into the skeletal muscles during extended
    recovery intervals.


    Ken Russell

  • “As a scientist…”

    Your uncontrolled example describes more of a neurological adaptation (coordination, recruitment, synchronization, etc…) than a physiological change.

  • mark

    1/The solution may be a strain-gauge based unit, the best of which, (Mike Hefner’s “1 Rep Gym”), could easily be modifed by the manufacturer to suit NASA’s space constraints,(no pun intended). Isometrics alone give no feedback to assure progressive resistance. The strain-gauge solves that problem. 2/Recuperation is much different in zero-G: When not working out, the trainee’s bodyweight resistance levels go back to zero, effecting a much more profound rest period than possible in gravity, so instead of the usual 3 x wk workout sessions, there should be at least a 1-to-1 ratio of workouts & sleep periods. It may actually be best to do 5 or 6 different full-effort single-exercise workouts, equally divided throughout the waking period, to keep stimulating GH.


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