Space travel is certainly not for the faint of heart, for many reasons including its effects on physical health. It can potentially disturb human immune systems and increase red blood cell death. Astronauts can even suffer from bone loss during missions. It could also increase headaches. Astronauts with no prior history of headaches may experience migraine and tension-type headaches during long-haul space flights–over 10 days in space. The findings are detailed in a study published March 13 in the journal Neurology, the medical journal of the American Academy of Neurology.
“Changes in gravity caused by space flight affect the function of many parts of the body, including the brain,” W. P. J. van Oosterhout, study co-author and a neurologist at Leiden University Medical Center in the Netherlands, said in a statement. “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.”
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The study looked at 24 astronauts from NASA, the European Space Agency (ESA), and the Japan Aerospace Exploration Agency (JAXA). All of the astronauts were assigned to International Space Station expeditions for up to 26 weeks from November 2011 to June 2018. Combined, the astronauts studied spent a total of 3,596 days in space.
The astronauts all completed health screenings and a questionnaire about individual headache history before their space flight flight. Nine of them reported never having any headaches prior to the study, with three reporting a headache that interfered with their daily activities within the last year. None of the astronauts had a history of recurrent headaches or had a migraine diagnosis.
During space flight, they filled out a daily questionnaire for the first seven days and a weekly questionnaire each following week throughout their stay in the International Space Station. The astronauts reported 378 headaches during their combined days in space.
The study found that 92 percent of the astronauts surveyed experienced headaches during space flight, compared to just 38 percent who reported experiencing headaches in the two to six months before going into space. Twenty-two of the 24 astronauts studied also experienced one or more headache episodes during their first week in space. About 89 percent of these headaches were tension headaches and 10 percent were likely a migraine. Headaches were also of a higher intensity and more likely to be like a migraine during the first week of space flight.
According to van Oosterhout, the changes to the brain’s balance and posture system, combined with adjusting to zero gravity during the first week of space flight, “can lead to space motion sickness in the first week, of which headache is the most frequently reported symptom. Our study shows that headaches also occur later in space flight and could be related to an increase in pressure within the skull.”
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The astronauts were monitored after returning back to Earth and none of them reported any headaches in the three months after returning home.
One of the study’s limitations is that it relied on self-reporting of symptoms, so the memory recall may not have been fully accurate. It also didn’t say that going into space causes headaches, only shows an association.
“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,” said van Oosterhout. “Also, more effective therapies need to be developed to combat space headaches as for many astronauts this [is] a major problem during space flights.”
