Astronauts can easily lose bone and muscle mass in space because their bodies don't have to do a lot of work to move around in zero gravity, but wasting away above the planet is not an option. On Thursday two astronauts at the International Space Station took part in a Google hangout to show the world that they spend enough time working out to put many Earthlings to shame — a characteristic they share with Olympians.
Back on Earth, experts say we should try to exercise for at least 30 minutes a few times a week.
In space, according to astronauts Mike Hopkins and Rick Mastracchio, it's more like 90 to 120 minutes every 24 hours, and that's just so astronauts can maintain their fitness level. The astronauts spent around 20 minutes talking about their workout routines with a panel that included a member of the Houston Texans, a Crossfit champion, a United States bobsled team member preparing for the Sochi Olympics and another astronaut who joined the talk from Earth.
The conversation flowed from everyone asking each other about their workout regimens, including bobsledder Curt Tomasevicz's lengthy back-and-forth with the astronauts. Tomasevicz asked about everything from how the astronauts prepare to reenter Earth to how much Hopkins and Mastracchio can bench, while the astronauts questioned him about the bobsledders' preparation in the weeks leading up to their Olympic runs.
See also: 20 Epic Space Photos From Astronaut Chris Hadfield
Hopkins and Mastracchio started their explanation of space workouts by displaying the space station's workout material — an adaptive resistance machine, a treadmill and a cycling machine they use daily to get in their weightlifting and aerobic workouts, which are based on individual body type and planned by NASA trainers. They spend a lot of time on the resistance machine, which serves as a weight-lifting device by pushing down on the astronauts as they lift up, and it allows them to do a number of exercises, from squats to dead lifts to bench presses.
"A lot of it's the same — your muscles get sore, you get tired," Hopkins said. "On the other hand, you do have to get used to this machine, because it doesn't operate quite the same way that you're used to on the ground."
The idea is to prevent any vibrations from the workout from affecting other activity on the space station, so the resistance machine moves with the astronaut, countering their motions and preventing them from rocking their temporary home.
The way astronauts sweat, though, is something hardly replicable on Earth.
"Instead of the sweat running down your face or running down your body, it just basically pools on your arm or on your body," Mastracchio said. "And if you shake your head, basically sweat goes everywhere."
And astronauts sweat a lot. They have to, because without exercise their body mass would shrivel to the point that they'd have trouble walking for their first few days back on Earth.
"One of the problems both Rick and I have had up here is maintaining our weight," Hopkins said.
Hopkins said he has dropped 10 pounds since his six-month stint began last September, and he hasn't been able to get up to his usual 185 pounds despite being on a diet of nearly 3,000 calories per day and all that muscle-building exercise.
But that shouldn't affect him too much when he's back on Earth. Astronaut exercise regimens make it easy for them to adjust to gravity and the rest of life back on the planet. Without much muscle and bone loss, Mastracchio said he expects their recovery period to only last two or three weeks.
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