By Will Dunham, Reuters

WASHINGTON — Research in the expanding field of space medicine has identified many ways in which a microgravity environment and other factors can meddle with the human body during space missions. A new study has added to the field by showing that astronauts are more likely to experience headaches in space than previously known.

The study involved 24 astronauts from the U.S., European and Japanese space agencies who traveled aboard the International Space Station for up to 26 weeks. All but two of them reported experiencing headaches in space.

This was a larger proportion than the researchers had expected based on prior anecdotal evidence. The headaches — some resembling migraines and others resembling tension headaches — occurred not only during the first couple of weeks in space as the body goes through the process of adapting to microgravity, but also later.

The headaches occurring during the early period often present as migraine-like while those experienced later in space travel present more like a tension headache, the study found.

"We hypothesize that different mechanisms are involved for the early headache episodes — the first one to two weeks in space — versus later headache episodes," said neurologist W.P.J. van Oosterhout of Zaans Medical Center and the Leiden University Medical Center in the Netherlands, lead author of the study published this week in the journal Neurology.

"In the first week, the body has to adapt to the lack of gravity, known as space adaptation syndrome. This phenomenon is similar to motion sickness, and can cause nausea, vomiting and dizziness, and headaches," van Oosterhout said. "The later headaches could result from an increase in intracranial pressure. Due to microgravity, there is more fluid accumulating in the upper part of the body and head, resulting in higher pressure in the skull."

Migraines experienced on Earth are often throbbing and pulsating headaches lasting four to seven hours, accompanied by symptoms such as nausea, vomiting and hypersensitivity to light and sound, Van Oosterhout said. Tension-type headaches on Earth usually are a more dull pain felt over the entire head without those other symptoms, Van Oosterhout added.

https://www.ksl.com/article/50950154/study-documents-headaches-experienced-by-astronauts-in-space