Dutch scientists have discovered that a good number of astronauts have suffered "space headache" - a unique condition apparently unrelated to the usual woes of space motion sickness (SMS) and characterised by an "exploding" pain.

Researchers from the Department of Neurology at Leiden University Medical Centre questioned 17 veteran astronauts, of whom 12 admitted they'd endured headaches in space, "yet were headache free back on Earth", as the BBC puts it.

The Dutch teams accordingly concludes that space flights "may trigger headaches without other SMS symptoms in otherwise 'super-healthy' male subjects", and goes on to "propose to classify space headache as a separate entity among the secondary headaches attributed to disorders of homeostasis".

Among the possible reasons for space headache, the researchers consider microgravity a top candidate, since it causes lower blood oxygen and provokes "a shift in the body's fluid towards the brain which would raise intracranial pressure" - either of which could be the culprit.

Lead researcher Dr Alla Vein concluded: "Although headaches in space are not generally considered to be a major issue, our study demonstrated that disabling headaches frequently occur during space missions in astronauts who do not normally suffer from headaches on earth.

"Previous research has shown that astronauts can be reluctant to reveal all the physical complaints they experience in space, so the actual incidence could be even higher than our study suggests."

The team's findings are published in the International Headache Society's journal Cephalalgia. ®

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