It is known that women are more prone to migraine and that such attacks are usually related to menstruation cycle. Women also appear to be more prone to motion sickness and this susceptibility seems to follow their hormonal levels. This was examined in a group of mariners participating in yacht racing who were followed for the incidence of motion sickness and migraine correlated to their menstrual cycle. The researchers E A Grunfeld and his team from the Medical Research Council's Human Movement Balance Unit, London, report that women were most susceptible to motion sickness three days before menstruation and the frequency of headaches of all kinds was also greatest during this phase of cycle.