What are the health risks of space travel?

The concept of space tourism is quickly becoming a reality. But taking a trip to outer space isn’t as simple as it may seem. Before donning your spacesuit, there are a few things you should know about the effects that space travel can have on the human body.

First and foremost, space travelers must be screened for certain diseases, explains Richard A. Scheuring, DO, FAsMA, an osteopathic physician and a NASA flight surgeon. Health problems such as heart disease or diabetes cannot be easily managed during space travel.

“Before space flight, a really, really good physical should be completed by a doctor to rule out any potentially dangerous health issues,” says Dr. Scheuring.

Once an individual has been cleared to travel, the following health concerns should be taken into consideration.

Microgravity

When taking short-term (10-14 days) visits, the first major issue travelers will notice is balance.

“When they first get to space, it takes them a while to figure out what’s up, down, right, left, because part of your inner ear turns off and takes about a day or two for them to get oriented to microgravity,” explains Dr. Scheuring. Similarly, it will take travelers a couple of days to get their “sea legs” back on Earth upon returning.

An urge to urinate

Space travelers will also experience what is known as a “cephalad,” which occurs when the fluid in the legs moves towards your core and towards your head. Travelers will experience a stuffy head and the frequent need to urinate due to gravity not pulling blood into their legs.

After 2-3 days, the fluid balance becomes normal for space. But similar to the balance issue, it will take a few days upon returning to Earth for things to get back to normal.

While these are the two big changes space travelers will experience, Dr. Scheuring says there are other changes that will occur, especially for longer-duration trips.

Immunity

“There are other subtle immune changes that will occur when you’re up there for two or three weeks. Long-duration astronauts start developing a relative immunocompromised state because they’re basically in a sterile environment, so they’re not introduced to new bugs: no viruses, no COVID, nothing like that,” says Dr. Scheuring.

Upon returning to earth, space travelers must wait 3-7 days for their immune cells to “wake back up” and get their immunity back.

Back on Earth

What about the effects of traveling back to Earth? There are definitely some sensations that space travelers will feel during their return flight. Although return flights are usually quick, many travelers will get nauseous or throw up.

Upon trying to stand up, travelers may feel wobbly. To combat these issues, travelers should minimize the amount of time they’re standing by themselves. An IV with fluids will usually be started to counteract the volume loss, and gradual sips of water or Gatorade will be encouraged.

What lies ahead

Screening for diseases, anticipating changes in balance and fluids, understanding impacts on immunity, and preparing for re-entry—these are just some of the steps that space travelers will learn to take as the space tourism industry begins gaining traction.

“What’s exciting to me is that much of what we learn supporting astronauts actually translates to health improvements for everyone,” says Dr. Scheuring. “NASA scientists and physicians share their research with the healthcare community, leading to incredible advances in care for those who travel to space and for those here on Earth.”