New research explains why some individuals may get a headache at the same time each day.
For those who live with either cluster headaches or migraine, the disruption that comes from these types of headaches can be debilitating, impacting everyday life. For many, these serious headaches take place at the same time each day, bringing about a routine of pain and discomfort.
Recent research explains what might account for the onset patterns of cluster and migraine headaches. A meta-analysis, published in Neurology, examined all available studies on both migraine and cluster headaches that involved circadian systems. They paid close attention to the time of day, and the time of year that these headaches were occurring; circadian rhythms are heavily associated with light and dark, making these data points highly relevant.
They also assessed studies on the presence of these headaches and hormones like melatonin and cortisol, which are tied to one’s circadian system.
When looking at the data from the analysis of all of these studies, lead study author Mark Joseph Burish, MD, PhD, of the University of Texas Health Science Center at Houston and a member of the American Academy of Neurology, told Health that cluster headaches are well known among specialists “to have a precise daily cycle,” which meant they weren’t surprised to see this connection with the circadian system. It was the migraine data that surprised him the most.
“Migraine, however, is not thought of as a highly circadian disease,” Dr. Burish explained. “We were surprised to find that migraine has such strong circadian connections—50% of patients report headaches at the same time of day, there are lower melatonin levels in patients, and there are genetic connections to circadian genes or genes controlled by the biological clock.”
What Causes Migraine and Cluster Headaches?
While two kinds of headaches were studied in the new research, there are important distinctions between the two.
A cluster headache generally goes on for 30 to 90 minutes, while a migraine can last a full day or even several days if it goes unattended.2 A person will usually experience one migraine at a time, while cluster headaches can clump together up to eight in one day. Between these cluster headaches, you might experience a moment of reprieve, while the pain from migraine could fluctuate through the day but doesn’t subside completely, it lingers.
Cluster headaches involve just one side of the head—think around the eye or temple—while migraine headaches can be located all over the head.2
Rashmi Halker Singh, MD, an associate professor of neurology at Mayo Clinic who sits on the Board of Directors of the American Headache Society, told Health that genetic factors are at play in the presence of cluster headaches and migraine. She noted that she frequently sees patients who come to her frustrated as they try to get a handle on why they are experiencing these often extreme headache attacks.
“Migraine is much more common, people want to know why this happens to them,” said Dr. Halker Singh, who is unaffiliated with the new study. “This new study is really interesting in that it helps validate that—it helps identify that there are more genes involved in migraine, for instance, and also helps to point to additional brain areas that are important to [the presence of] migraine as well.”
Dr. Burish said a family history of these kinds of headaches raises one’s risk of experiencing them. He echoed Dr. Halker Singh in the belief that this is due to genetic links.
“A family history of cluster headache also raises your risk of having cluster headache, though not nearly as strong as migraine. Actually being a smoker, for reasons we do not understand, increases your risk of having cluster headaches,” he said.
The Timing of Heaches
The hypothesis that Dr. Burish and his team devised centers on the hypothalamus area of the brain, which regulates many bodily functions like one’s sleep cycles, body temperature, and even level of hunger. This allows individuals to focus on the timing of a headache.
“The hypothalamus is known to activate at the beginning of a migraine headache and at the beginning of a cluster headache. The hypothalamus also controls your circadian rhythms, so we think that the headaches are tapping into the circadian rhythm system,” he said.
Dr, Halker Singh explained that it’s important to keep in mind that migraine and cluster headaches are two very different medical conditions. She explained how this research reinforces how a circadian rhythm can regulate a phenomenon like a cluster headache.
She continued, stating how sleep can be restorative for migraine but the irony is many people who experience them, unfortunately, find a migraine waking them up in the middle of the night. But it’s not sleep that’s waking them up—it’s, again, tied to the circadian rhythms and hypothalamus.
Preventive Measures for Cluster Headaches and Migraine
Dr. Burish offered some current treatment options for these kinds of headaches. He noted that these treatments are split into two different categories: acute medications and preventative medications. Acute medications are things taken during the headache in order to break it, while preventative medications are things taken regularly in order to reduce the frequency and intensity of headaches.
“Some of the preventive treatments for cluster headache and migraine, like prednisone and melatonin, are known to alter the circadian clock. But there are not a lot of other current medications that alter the circadian clock,” he explained.
Dr. Burish also noted that by better understanding the role of the circadian clock in headaches, there is the potential to develop new drugs down the line “to prevent the headaches when they are most likely to occur.”
Next Steps in Headache Research
One limitation of the new study was a lack of information on the factors that could influence a person’s circadian cycles. When asked how having this information could further their understanding of these headaches and how they behave, Dr. Burish said there would be “more detail about the best way to help patients.”
“For example, working the night shift changes your circadian rhythms because you are awake and active when your body naturally would be asleep,” Dr. Burish explained. “If we find that working the night shift changes your headaches in a certain way, we could try to design drugs that either mimic or counteract the effects that the night shift has on your circadian rhythms.”
Dr, Halker Singh said this kind of research is incredibly validating for people who live with these headaches and are searching for an answer to why they are happening.
“We don’t have a test at this time to give a diagnosis for migraine. The diagnosis comes by talking to my patients and helping them come to a diagnosis—it can be validating to have research that shows abnormalities that correlate to what’s going on with them,” she explained.
She added that she’s hopeful about potential future research that could lead to possible new treatments.
According to Dr. Burish, that’s part of the plan.
“We think that looking more into the effects of the circadian rhythms on the hypothalamus, headache genes, and current headache medications is the next step,” he said. “With that information, we hope we can identify specific triggers for the headaches that we can then target with medications.”
