Running a marathon is tough. But what about
running one in space? But how hard can that be? Hello moon walkers, Lissette here for DNews.
Astronauts in space live in a whole different world. And one of the biggest differences,
besides probably the lack of oxygen, is the lack of gravity. Thanks to this we have some
pretty cool images of suspended water bubbles and astronauts walking on the ceilings of
space shuttles. But, the microgravity present in space also poses some challenges – namely,
the impact it has on an astronaut’s body. We don’t really notice, because we’ve
habituated, but on planet earth, our body is constantly working out. Gravity pulls us
down and our muscles and bones must resist that tension to keep us upright and moving
– sorta like mini workouts. But, in space, this tension virtually disappears. Which is
really bad, because muscles can atrophy and bones can lose density. Just like muscles,
bones are living tissues that need exercise to stay healthy. This is why on average NASA astronauts spend
2.5hrs per day working out in space. But it looks a bit different from what we see here
on earth. Pushups, jumping jacks, running, or anything really that doesn’t involve
equipment, just doesn’t work for them. They use special exercise machines. The three main
ones at the International Space Station are the Colbert, Cevis, and Ared. The Colbert,
named after this guy, is actually short for Combined Operational Load Bearing External
Resistance Treadmill. It is basically a treadmill but astronauts must be harnessed in place.
The Cevis or Cycle Ergometer with Vibration Isolations and Stabilization System is like
a bicycle, but because without gravity you can’t sit down, astronauts stand and strap
their feet to pedals. Lastly, the ARED or Advanced Resistive Exercise Device resembles
a weight training machine which can be used for things like deadlifts, calf raises and
squats through a piston-driven vacuum cylinder and flywheel system. All of these modifications are necessary because
objects lack any weight and regular lifting would be way too easy. So does this mean all
regular exercise is easier in space? Not, exactly. Zero gravity does mean that the lack
of resistance might make it easier for astronauts to lift things that would weigh hundreds of
pounds on earth. But here’s the thing. While in space your body fluids, sort of just float
all around your body. Without gravity there is nothing to pull blood down below the heart
to your legs and toes. The vast majority of blood just hangs out around the heart and
head. So astronauts have less plasma and red blood cells to carry oxygen to their muscles.
This is a problem for things like running or burpees because the lack of oxygen can
cause dizziness, and therefore impede performance. Still, despite the hours spent working out
everyday with specialized equipment, astronauts bodies take a toll. On average, NASA reports
that they suffer decreases of 11 to 17% of their muscular strength and about 10% of their
muscle endurance. Their bone density also tends to decrease about 2 to 7%. And according
to an International Space Station scientist, about 80% report feeling lightheaded shortly
after returning to earth. This is largely why scientists have multiple studies underway
to figure out how to improve exercise in space and diminish the negative health effects of spaceflight.