Headaches appear to have a correlation with circadian rhythms and the genes and hormones that regulate them: a fact that may help in treatment.
If you suffer from headaches, pay attention: do they always seem to come back in the same time slot? According to a study published in the medical journal Neurology this is likely to be the case. The work has in fact found a strong link between some types of headache (migraine and cluster headache) and circadian rhythms, ie our “internal clock” spread over a 24-hour cycle.
Two kinds of pain. Cluster headache is a very intense, localized form of headache (usually around the temple or in an eye socket) that manifests itself in usually short but regular attacks, repeated over a period of 1 to 3 months, followed by an asymptomatic stage. Migraine is the most common form of headache, one that starts in the front or side of the head and spreads, accompanied by nausea, sensitivity to lights and sounds.
Looking for connections. The research reanalysed all available scientific studies on these two types of headaches that included information on the circadian rhythms of affected patients: data on the time of day or year when the disorder manifested itself, on the genes that influence both susceptibility to the headache both the disturbances in the biological clock, or still on the levels of hormones (such as cortisol and melatonin) that regulate circadian rhythms, and which can contribute to the onset of headaches.
Punctual ailments. Cluster headache was found to follow a consistent circadian rhythm in 71% of the patients considered. Attacks typically peaked late at night or in the early morning hours, intensifying in the spring and fall. This type of headache also appeared to be associated with two important circadian genes, and five of the nine genes that increase the likelihood of suffering from cluster headaches are genes with expression strongly regulated by circadian rhythms. Those affected by this disorder also typically have higher cortisol levels and lower melatonin levels than those without it.
As for migraine, attacks follow circadian rhythms in half of the patients. The times seemed less regular and more widespread during the day, but there is a moment of the night when the episodes are rarer. Migraine is also associated with two important genes that regulate circadian rhythms, and 110 of the 168 migraine-related genes are expressed according to the body’s internal clock.
Migraine sufferers have lower levels of melatonin in their urine than normal, especially during attacks.
Silent director. “The data suggest that both of these types of headaches are highly circadian at multiple levels,” says Mark Jospeh Burish, a researcher at the University of Texas at Houston and first author of the study. “This reinforces the importance of the hypothalamus, the area of the brain that houses our primary body clock, in the onset of migraines and cluster headaches. And it leads to wondering what role (in this disorder) the genetics behind triggering events such as sleep changes play, at the same time known causes of headaches and signals of how the body’s circadian rhythms work.”
Therapeutic perspectives. The findings open up the possibility of using treatments to regulate circadian rhythms to treat recurring headaches, or to make simple adjustments in therapies, such as taking medicines at specific times of the day.