What happens to muscles in space?

I've heard that muscles can waste in space because of decreased gravity. Does that mean astronauts return to Earth really weak? Are they up there on the ISS weightlifting...
23 May 2017

Weak muscles

Weak muscles



What happens to muscles in space?


Chris - Now Richard, Sam has got in touch to ask about muscles in space. He asks “I've heard that muscles can waste in space because of decreased gravity. Does that mean astronauts return to Earth really weak? Are they up there on the ISS weightlifting everyday?”

Richard - Yes. Space is really bad for you because there’s no gravity you get muscle loss, so astronauts have to exercise two hours a day every day of the week. Even then, they return to Earth with weakened muscles. More seriously, there’s a loss in bone density as well, which is useful for studying astronauts in space because that might be applied to osteoporosis or other diseases on Earth.

Other things that astronauts experience - lack of sleep. That’s partly because you’ve got daylight every ninety minutes or so. Eyesight gets worse; they don’t entirely know why that is yet. You’ve got the radiation risk, so increased risk of cancer - you get zapped by cosmic rays all the time. There’s even weakened immune system - again they don’t know the entire reason for that. So, space is bad!

Scott Kelly spent a year in space and they reckon he’s going to take another year to recover fully. Peggy Whitson, currently up on the space station, she knows hold the record for 560 days in space. But these are all super fit people when they go up but it does take awhile to get back.

My favourite quote on this is from Bones in Star Trek from the first of the new Star Trek movies “space is disease and danger wrapped in darkness and silence.”

Chris - It’s good to see Star Trek quoted on the programme. Jess?

Jess - Does anything good happen? There was that story about Scott Kelly - do you not get taller when you come back from space?

Richard - Yes you do. But that in itself is a problem because you’re fitted for your space suit to go up, and actually getting back they’re taller - they literally squeeze them in. They have to make the seats slightly bigger so when they come back they will fit in the seat.

Jess - They are recycling the suits all the time any way, right? They don’t make the suit just for you?

Richard - No. They do make the suit just for you so you do have your own space suit. So you’re fitted - they have these special suit checks and everything.

Chris - And they’re incredibly expensive too aren’t they?

Richard - Yeah, but weirdly, they’re still laced up. They are basically the same space suit, more or less, that Yuri Gagarin flew in. But they are extraordinary - they're very old technology. They’re laced up and they’re kind of wrapped in on themselves.

Chris - Kate?

Kate - How does skin react to being in space? Do astronauts have to moisturise all the time or are they holding their moisture much better?

Richard - I would imagine it’s an issue because it’s not so much that they’re in space, it’s that they’re in this rather nasty air-conditioned environment.


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