The Impact of Biseasonal Time Changes on Migraine.

Background: Changes in the daily rhythm can trigger migraine attacks. The sensitivity for triggering attacks is closely linked to the regulation of biological rhythms controlled by the hypothalamus. In over 70 countries around the world, the time is changed between daylight savings time and standard time twice a year due to legal regulations. The aim of this study was to investigate whether the time change has an influence on migraine. Methods: In this retrospective study, the headache frequency of patients with episodic or chronic migraine at a tertiary headache center in the years 2020, 2021, and 2022 was evaluated. The primary outcome measure was the frequency of migraine occurrence on either Sunday or Monday of the time change weekend compared to Sunday or Monday before or Sunday or Monday after the time change. Results: Data from 258 patients were analyzed (86.8% women; average age: 51.5 years; average headache frequency: 7.7 days/month; 83.3% episodic migraine). Our results showed a significant increase of 6.4% in migraine frequency on the Sunday and/or Monday in the week after the time change in spring compared to the week before the change. In autumn, conversely, there was a significant reduction of 5.5% in migraine frequency on the Sunday and/or Monday one week after the time change compared to the week before the change. The factor responsible for the significant changes was the increase in migraines on Monday one week after the time change in spring and the decrease in migraines on Sunday one week after the time change in autumn. Conclusions: When switching from standard time to daylight savings time in the spring, the frequency of migraines increases significantly one week after the time change. In autumn, in comparison, there is an inverse trend with a reduction in migraine frequency. These data suggest that synchronization is disturbed when switching to daylight savings time. Conversely, synchronization normalizes in autumn. In view of the high prevalence of migraines, this can have extensive individual and social consequences.