Imagine trying to swallow a sip of water while your face feels stuffed with congestion, your sense of taste is dulled and your body is floating 250 miles (400 kilometers) above Earth.

That scenario is part of everyday life for astronauts aboard the International Space Station.

Spaceflight changes the human body in dramatic ways. Muscles shrink, bones lose density and bodily fluids shift toward the head. Astronauts often return with puffy faces, stuffy noses and a feeling similar to a lingering cold. When you’re congested, you might have more difficulty swallowing – but does microgravity also affect this important body function?

As a speech-language pathologist and researcher who studies swallowing disorders, I spend much of my time thinking about how to help people eat and drink safely. When everything’s working smoothly, swallowing feels effortless, but it is one of the most complex actions the human body performs.

Every swallow requires more than 30 muscles and several nerves to work in perfect sequence. Food and liquid must move from the mouth to the stomach while the airway closes in a fraction of a second to keep material out of the lungs.

Most people complete this........

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