Can You Get Sick in Space?

Having a cold is no fun, your throat feels scratchy, your nose gets runny, and you seem to be sneezing every few minutes. In Space, having a cold is even worse. Can you get sick in Space?

In 1968, NASA’s Apollo 7 spacecraft blasted off with a three-person crew aboard. Just 15 hours into the mission, astronaut Wally Schirra caught a cold. The other two members of the crew were quickly infected. 

Along with normal cold symptoms, the “space-colds” made it extra hard for the astronauts to relieve their discomfort. In outer space, the absence of gravity means that nothing is pulling down on your body— or your snot! As the mucus collects inside your nose, it gets stuck and starts to feel stuffy. 

The astronauts tried using tissues to blow their noses, but that didn’t help either. When you have a cold, whether on Earth or in space, too much mucus buildup causes ear pain. That’s because of the eustachian tube, a secret tunnel connecting your ear to your nose. When the tube fills up with mucus, it puts pressure on your eardrums, causing them to feel painful and blocked. 

The astronauts found that blowing their noses made the ear pain even worse. With the help of some aspirin, the crew members were able to manage their difficult symptoms until they finally returned to Earth.

Since then, NASA has required detailed medical examinations before astronauts can be approved for any spaceflight missions. NASA has also researched how Schirra was able to infect the other astronauts aboard the spacecraft so quickly. In NASA’s Integrated Immune study, scientists found that space travel damages the immune system. Your immune system is in charge of protecting your body from toxic materials that can make you sick.

Normally, your immune system cells are in balance. They stay on stand by unless there is an immediate threat and activate when harmful materials enter your body. Instead, the study found that immune system cells switched between super-high and low levels of activity in space.

sick in space

In low levels of activity, the immune system cells ignored all toxic materials, leaving the immune system completely defenseless against dangerous germs! On the Apollo 7 mission, low activity levels in the immune system could explain why Schirra’s cold was so contagious. The astronauts’ immune systems did not recognize or fight against Schirra’s germs at all! On the other hand, high levels of activity cause the immune system to completely overreact. Immune system cells start activating even when there are not any germs to fight off. When this happens, you might see rashes or red spots pop up on your skin. 

If you’re allergic to anything right now, you might not have that allergy forever! Over time, you may develop acquired immunity as you get older and have more physical contact with your allergens. If you develop acquired immunity, it is considered long-lasting. That means you won’t have those allergic reactions ever again… Unless you travel to space! In NASA’s study, astronauts had strong allergic reactions to foods that they had developed immunity against many years ago. Common signs of allergic reactions include swelling, itching, and feeling dizzy. 


Besides the “broken” immune system, these allergic reactions were affected by the astronauts’ bones! Immune system cells actually come from bone marrow, a squishy mixture inside your bones. On Earth, gravity pulls down on your bones. Whenever you want to run,  walk, or jump, your bones are moving against the force of gravity. In space, this imbalanced immune system response can also cause a return of childhood allergies. The extra work your bones do keeps them strong and even helps you grow!

In space, without gravity, your bones don’t have to work as hard and start to lose their minerals.

As your bones weaken, so do the immune system cells that develop within the marrow. Those cells have trouble remembering which items or foods are toxic. So, they react to old, childhood allergies even though they developed acquired immunity against them.

Luckily, astronauts can strengthen their bones by exercising often. Lifting weights or running on a treadmill mimics the work that our bones do on Earth. This helps their bones retain more minerals and their immune systems better retain their memories. Future astronauts must be prepared to face these new conditions. But, whether you’re on Earth or in space, it’s always a good idea to take care of your health!



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