Yachtswomen racing around the world for nine months will record details of sea sickness and menstrual cycles to help scientists understand motion sickness.
Michael Gresty's team at the Medical Research Council's human movement and balance unit at the National Hospital in London, expect the British Telecom Round the World Yacht Race, which started in Southampton last weekend, to shed light on the link between motion sickness in choppy seas, migraine attacks and the female cycle.
"Some people get very ill from rough conditions and it seems to be disproportionate to having normal motion sickness," said Dr Gresty. "They get throbbing headaches, and bowel movement changes.
"Women are three times more susceptible to migraines than men and are especially likely to get one when they have big hormone changes. They are also more likely to suffer from motion sickness."
Dr Gresty hopes that up to 60 women will take part in the study, along with the 130 men in the race who will act as controls.