Yom Kippur headache.

Fasting is frequently mentioned by patients and in textbooks as a trigger for headache. In this study, we attempted to define the role of fasting as a possible precipitator of headache. Headache history was documented in 370 hospital employees (60% female) before and immediately after a 25-hour fast for the 1993 Day of Atonement (Yom Kippur). The population included 211 who fasted; 39% of fasters developed headache, compared with only 7% of nonfasters (p < 0.000001). Headache was usually of a nonpulsating quality, mild to moderate in intensity, and bilateral and frontal in location. Subjects with a history of headache were more likely to develop fasting-induced headache than were those without such history (66% versus 29%, p < 0.000002). The number of headache sufferers increased in direct relation to the duration of the fast. Caffeine and nicotine withdrawal and oversleeping did not appear to have an influence on headache development. We conclude that fasting is a strong headache precipitator, especially among chronic headache sufferers. It is usually nonpulsating and nonlateralized.