Breaking free of the the Earth's gravity and floating in zero-G: It's certainly a thrill for those who get to experience it, either through traveling to space or simulating the journey. All good things, though, must come in moderation. Too much time free from the grip of gravity and we turn into weak-muscled wimps, which is a huge hurdle for hopes to travel to Mars or deep into space. Robert Fitts wanted to know just how quickly the lack of resistance on one's muscles makes them out-of-shape and atrophied. So his team tested nine astronauts before and then just after their six-months stays aboard the International Space Station. The study appears this week in the Journal of Physiology.
The losses in fibre mass, force and power translated into a decline of more than 40 percent in the capacity for physical work, Fitts reported. Ironically, beefing up before the trip had no impact on muscle loss. In fact, crew members who began with the biggest muscles turned out to have the biggest decline in muscle fitness [AFP].
And it's not like astronauts are eating Doritos and watching marathons of Lost In Space up there. NASA knows the muscle problem full well, and the astronauts aboard the ISS adhere to a strict exercise regimen that requires running on a treadmill 2 and a half hours a day nearly every day, with harnesses holding them down so they can "walk" in zero-G. There's nothing like the real thing, though.
“The lack of load” — pressure on muscles — “is the main problem,” said [Fitts]. “There is no gravity and so any fibers within those muscles are unloaded. The load normally maintains protein synthesis and the size.” Even with plenty of activity, the lack of load leads to atrophy [Wired.com].
If this sounds familiar, it is: We reported last year on a similar study
that said living in space gives healthy astronauts the muscle tone of elderly people. But Fitts' study suggests the deterioration is even worse. Which makes one wonder: How are human explorers going to get to Mars without withering away to nothing? These ISS missions last six months. For a prospective mission to Mars
, astronauts could be traveling 10 months in each direction with a year stay on the red planet in between. That means they'd be gone from the Earth for nearly three years, or six times longer than the ISS astronauts. Without a better system to stave off muscle atrophy, they'd never make it. With the new Advanced Resistive Exercise Device
, NASA's Lori Ploutz-Snyder says, the ISS at least has the first piece of a better system.
Installed in November 2008, the ARED allows astronauts to perform a variety of weight-training exercises, such as squats and bench presses, with loads of up to 600 pounds. How do astronauts weight-train in zero gravity? Ploutz-Snyder said the ARED generates loads using vacuum cylinders. It also has flywheels to generate the inertia needed to get the load off the rack [Space.com].
But let's be honest. What we really need is to invent Star Trek-style artificial gravity so we can head for Mars without having to run three hours every day and avoid seeing our muscles turn to goo. Related Content: DISCOVER: Space Travel for Every Budget
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