Them’s Rough Waters, Matey: Beware of Migraines

Rough seas can trigger migraine headaches in some people, although headaches and motion sickness do not always go together, according to a British study of sailors in a long-distance ocean regatta.

Researchers said the findings show that motion sickness and migraines, despite their similar symptoms, occur independently in most people, although “exposure to rough seas could be a migraine trigger in certain individuals who did not otherwise have attacks.”

Female sailors were most susceptible to motion sickness and headaches during their menstrual cycles--from three days before menstruation to the fifth day of menstruation, the study found. In males, the headaches were not cyclical.

Because women are more prone than men to both migraine headaches and motion sickness, some researchers have speculated that a common hormonal cause might be at work. But separating out the two effects is difficult because there is considerable overlap in their symptoms, including nausea.

British researchers attempted to clarify the issue by studying 111 sailors, including 34 women, who competed in last year’s Global Challenge race from Boston to Southampton, England.

The race, which has six legs ranging from eight days to 45 days, routinely exposes sailors to rough seas in the North Atlantic, and seasickness is common among the competitors.

The study was conducted by researchers from the National Hospital for Neurology and Neurosurgery in London. They reported their results this month in a research letter to the Lancet.

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Before the race, the sailors filled out detailed questionnaires designed to measure their susceptibility to motion sickness and headaches. During the race, about half of the sailors also kept daily logs, recording headaches, symptoms of motion sickness, medications taken and menstrual cycles.

Twelve of the sailors--nine women and three men--had migraine headaches at sea, averaging five attacks apiece. Only eight of those 12 had reported migraines before sailing.

An additional six sailors were found to have migraine disease before the race, but did not experience any migraines during the race despite the rough seas.

Those who had migraines while at sea suffered more bouts of motion sickness, on average, than other sailors during the race.