"Understanding the Reason for Daily Headaches at a Consistent Time: Insights from a Study"

New research has shed light on why some individuals may experience headaches at a specific time each day. These headaches can be debilitating and greatly impact daily life for those who live with cluster headaches or migraines. A recent meta-analysis, published in Neurology, examined studies on both migraine and cluster headaches that involved circadian systems. Researchers paid close attention to the time of day and time of year the headaches occurred. They also assessed studies on the hormones melatonin and cortisol, which are tied to one's circadian system.

Lead study author, Mark Joseph Burish, MD, PhD, of the University of Texas Health Science Center at Houston, explained that cluster headaches are known to have a precise daily cycle, so it was not surprising to see the connection with the circadian system. However, the data on migraines surprised researchers. Dr. Burish stated, "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."

Although the meta-analysis included both types of headaches, there are important differences between the two. A cluster headache generally lasts 30 to 90 minutes, while a migraine can last a full day or even several days. Cluster headaches typically occur on one side of the head, while migraines can be located all over the head.

Dr. Rashmi Halker Singh, an associate professor of neurology at Mayo Clinic, explained that genetics play a crucial role in the presence of cluster headaches and migraines. She noted that many patients who experience these extreme headache attacks are frustrated and seeking answers. Dr. Singh stated, "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 and his team hypothesize that the hypothalamus area of the brain, which regulates bodily functions like sleep cycles and body temperature, plays a critical role in the onset of these headaches. "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.

It is important to note that cluster headaches and migraines are two very different medical conditions. Dr. Singh emphasized the importance of understanding how a circadian rhythm can regulate cluster headaches, and how sleep can be restorative for migraines. Nevertheless, many individuals with migraines unfortunately find themselves waking up in the middle of the night due to their condition, which is again tied to circadian rhythms and the hypothalamus.

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.”

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.”