International Space Station Living Can Affect the Body in the Most Unusual Ways

posted: 03/08/17
by: Rachel Riederer

There are currently six astronauts living onboard the International Space Station. As they orbit the Earth, the crew conducts all kinds of research experiments in the microgravity environment. And some of the most important knowledge that comes from the ISS comes from the astronauts' own bodies. In that extreme environment, "some really funky things happen to your body," says astronaut Leland Melvin, who has completed two missions to the ISS. Among other things, after his time away from Earth's gravity, Melvin came back to Earth an inch taller.

Why would time in space make a person grow? On Earth, the downward pull of gravity causes compression of the vertebrae--without that gravity, the spine expands, and this lengthening makes astronauts taller. Astronaut Scott Kelly, who in 2016 returned from a yearlong tour on the ISS, was a full two inches taller on the space station than he had been before the mission.

But a lengthening spine is the least of the bodily changes that astronauts undergo on the ISS. The reduced gravity can also change the pressure of the fluids in astronauts' heads, which can lead to pressure building up on the optic nerve, resulting in changes in vision. They never know how much a person's vision may change, so the ISS stocks extra pairs of glasses in a variety of prescriptions, just in case.

Our hearts are used to pumping hard to get blood to travel upwards from our lower body, against the pull of gravity. Without that resistance to work against, astronauts' hearts actually change shape and shrink in size. Similarly, muscles can atrophy because, floating in the ISS, astronauts don't have to work against gravity's resistance to move themselves around. The key to avoiding these ill effects--on space as on Earth--is exercise. On the ISS, astronauts exercise for an average of two hours a day, using equipment that's specially designed for this low-gravity environment.

Often, the human health research from the ISS turns out to be just as useful back here on Earth. For example, knowing that astronauts in the micro-gravity environment experience a loss of bone density, NASA conducted a study to see how much those effects could be offset by taking a supplement called bisphosphonate, which helps bones retain important minerals. The study not only benefitted the astronauts, but also bedridden patients and the elderly back here on Earth, who also experience bone loss and can benefit from the same treatment.

The latest rocket shipment of supplies to the ISS contained some research material that sounds quite hazardous to human health--a sample of the drug-resistant "superbug" MRSA. The bug mutates here on Earth, and researchers suspect it may mutate even faster in the stressful conditions of a micro-gravity environment. Seeing how the bug mutates in space would give health researchers here a head start, a glimpse into how the bug might behave in the future. And this would allow them to get a head start on designing life-saving drugs.

For anyone concerned about a dangerous bacteria being kept in such close quarters to the crew of the ISS: don't worry. The MRSA is locked up tight in three levels of containment. The crew members can breathe easy, and focus on their research and workouts.

Explore Discover Life! We're probing questions about Mars, from how humans might live there to where alien life might be hiding to survive the extremes. Plus, find out how we're preparing for the journey via extended stays on the ISS.

This experience is brought to you by the sci-fi thriller LIFE, in theaters March 24th.

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