1. Introduction
pain, CM, Migraines, migraines, migraine, Migraine
MIGRAINES, MIGRAINES, MIGRAINE, CHRONIC PAIN, MIGRAINE
Migraines are the most common cause of chronic pain. Effective, non-pharmacological strategies to reduce migraine load, like exercise, are needed, but it is unclear how exercise timing and chronotype modulate the effects. We sought to determine the effects of time-of-day of exercise, and synchrony with one’s chronotype, on migraine load. We performed a pilot cross-over randomized trial where participants with chronic migraine completed two one-month exercise interventions, consisting of either morning exercise (before 09:00 a.m.) or evening exercise (after 7:00 p.m.) in a randomized repeated measures cross-over design (Clinical Trial #NCT04553445). Synchrony was determined by exercise time and chronotype (i.e., a morning type participant exercising in the morning is ‘in-sync,’ while an evening type participant exercising in the morning is ‘out-of-sync’). Migraine burden, and anthropometric assessment occurred before and after each month of exercise. Data was analyzed using repeated measures ANOVA with significance accepted at Chronic pain affects millions of US adults each year, with chronic migraines (CMs) being one of the most common forms [Exercise is likely the most accessible non-pharmacological intervention capable of reducing migraine load in people with CM. Exercise interventions, including aerobic or resistance training, have been shown to decrease migraine frequency, pain, duration, and the number of migraine days [Circadian rhythms are recurring ~24-h cycles of physiological processes, allowing temporal synchrony with our environment. These rhythms are driven by endogenous (the transcriptional feedback loop, known as the circadian clock) and exogenous (environmental cues, like light) factors, and synchronized by a specialized brain region called the suprachiasmatic nucleus (SCN) [The time of day of exercise has previously been shown to modulate the perceptual, physiological, and biochemical responses to exercise [