Astronauts who have never had headaches may develop migraines and other tension-type headaches for the first time when they go into space.

A side effect of zero gravity, these headaches start with motion sickness as astronauts adapt to long-haul space flight, according to new research published March 13 in the journal Neurology. 

“Changes in gravity caused by space flight affect the function of many parts of the body, including the brain,” said researcher Willebrordus P.J. van Oosterhout, of Leiden University Medical Center in The Netherlands. “The vestibular system, which affects balance and posture, has to adapt to the conflict between the signals it is expecting to receive and the actual signals it receives in the absence of normal gravity.”

His team studied 24 astronauts from the United States, Japan and Europe who were deployed to the International Space Station between 2011 and 2018. The astronauts spent a combined total of of 3,596 days in space.

Before the study, none reported a history of recurrent headaches or had ever had a migraine, though three said they had had a headache in the previous year that interfered with their daily activities.

Nine astronauts said they had never had an headache.

Each completed a headache history questionnaire before their space deployment, a daily questionnaire for the first week of their mission and weekly questionnaires after that.

In all, they reported 378 headaches in flight.

Ninety-two percent had headaches during their mission, compared to 38% before. The vast majority — 90% — were tension-type stress headaches; the rest were migraines.

More intense headaches and migraine-like symptoms were more common during the first week in space, researchers found. During that period, 21 astronauts had one headache or more — 51 in all. Of those, 39 were tension-type headaches and 12 were migraine-like or probable migraines.

There was better news when the astronauts returned to Earth. In the three months after they came back from space, none reported headaches. 

“Further research is needed to unravel the underlying causes of space headache and explore how such discoveries may provide insights into headaches occurring on Earth,” van Oosterhout said in a journal news release. 

The study doesn’t prove that space travel causes headache, only that there’s a link.

In any case, van Oosterhout said, effective therapies to combat space headaches are needed since they are a problem for many astronauts.

More information

Baylor College of Medicine has more about how space travel affects astronauts’ health.

SOURCE: American Academy of Neurology, news release, March 13, 2024