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Cluster headaches are a unique neurological condition in many ways. One of the most interesting aspects of cluster headaches is how they seem to be aggravated or brought on by seasonal changes.
Episodic patients tend to go into cycle when the seasons change, particularly in the Fall and Spring. Chronic clusterheads see an increase in attack frequency during these times as well. Episodic cycles and high cycles for chronic patients are common around the equinoxes and when the days are longest (July, August) and shortest (January, February). Some patients can even predict their cycles to the exact day, and that predictability can have a profound impact on your mental health. The link to certain times of the year is so strong that March 21st has been dubbed Cluster Headache Awareness Day in Europe and the United States because it’s around the Spring Equinox.
Cluster headaches have a distinct clinical phenotype that’s often unmistakable (despite high rates of misdiagnosis). The attacks come on quickly, marked by a strictly unilateral (one-sided) stabbing pain behind the eye and around the temple. Patients have autonomic symptoms, are agitated and restless, and attacks last up to 180 minutes (sometimes longer) and re-occur several times a day, often waking you from sleep. The seasonal impact on the attacks could explain why cluster headaches are often mistaken for sinusitis or allergies.
This seasonal link is fascinating, and the theories as to why also help explain why the attacks occur at the same times each day. It all comes down to the hypothalamus, an almond-shaped part of the brain responsible for hormone production, the sleep-wake cycle, and many other critical jobs.
The Role of The Hypothalamus in Cluster Headaches
The cause of cluster headaches continues to be unknown, but researchers have identified the areas of the brain that are involved in acute attacks. First, the hypothalamus is activated. Then, the sphenopalatine ganglion—nestled deep inside your cheek behind your nose—and finally, the trigeminal nerve, which swells significantly during an attack. But what does the hypothalamus do?
The hypothalamus plays a crucial role and lives in the center of your brain, regulating the production of hormones and stimulating body processes. It maintains “homeostasis,” which translates to a healthy and balanced body. Found between the pituitary gland and thalamus the hypothalamus connects your nervous and endocrine systems to keep these body functions inline:
- Body temperature
- Hunger and thirst
- Emotions
- Sex drive or libido
- Heart rate
- Sleep cycles
- Blood pressure
- Bodily fluid balance
- Digestive juice production
Other areas of the body send alerts if something is unbalanced, and the hypothalamus responds by releasing the hormone related to that issue. Recent research believes that cluster headaches are caused by a “periodic dysfunction” of the hypothalamus, which can be caused by a myriad of factors ranging from your genetics to head trauma or disease. There are ongoing genetic studies for cluster headaches, and you can learn more on our Research page.
The Master Clock Inside Your Hypothalamus
Inside your hypothalamus is a structure known as the “Suprachiasmatic Nucleus,” or SCN. The SCN is your brain’s master clock that synchronizes your body state with the external changes that occur day and night. It organizes bodily functions such as when you eat or drink, body temperature, and hormone secretion into circadian rhythms that follow a daily cycle on a physical, behavioral, and mental basis. That goes for nearly all living things, including animals, plants, and tiny microbes. Even fungi such as mushrooms have innate timing devices. This master clock responds to the amount of light and dark in your environment and creates your sleep-wake cycle.
In cluster headaches, that was once thought to be a vascular headache disorder, the periodic nature of episodic cycles, and the precise timing of acute attacks are what pointed researchers to the hypothalamus. Melatonin—a hormone released when night falls to put you to sleep—is a standard preventive treatment used for cluster headaches, and abnormalities in cortisol and melatonin secretion have been demonstrated in cluster headache patients. This may explain why deep sleep, naps, and the aftermath of stressful events can trigger attacks.
The circadian rhythms instigated by your master clock regulate your sleep-wake cycle in relation to light. Environmental cues (namely changes in daylight) trigger your body to alter circadian rhythms—causing genes to turn on or off. That means that the changes in sunlight that come with a new season can reset, speed up, or slow down your biological clock. That alters your hormone levels, sleep cycle, and other components controlled by the hypothalamus. Cluster headaches are far from the only health condition linked to circadian rhythms. These times of the year also commonly affect mental health issues, sleep disorders, and even diabetes.
Cluster headaches are intriguing because you can nearly set your watch by them. Attacks occur at the same time in a 24-hour cycle and ramp up during specific seasonal changes. That precise timing has exciting implications for research according to a 2019 medical review, which discusses the potential for novel clock-modulating compounds to treat the condition.
What some may find fascinating is that if you were to move to a geographic area that doesn’t have the same seasonal shifts in daylight, you will likely still experience attacks or go into an episodic cycle. Similar to the way migratory birds in controlled environments still follow seasonal cues according to their biological rhythms.
You may be able to counteract the effect seasonal changes have on your cluster headaches by sticking to a strict sleep-wake cycle like going to bed within a 30-minute window each night and avoiding situations that can cause stress. However, without preventive treatment, you will likely still experience a spike in attacks if you’re chronic or the start of an episodic cycle when the seasons shift—Particularly in the Spring and Fall.