If you have ever been woken up by a headache in the middle of the night, you may have experienced what’s known as a hypnic headache. Hypnic headaches are considered rare, as they are thought to affect fewer than 1% of people. But if you’re one of the people who have them, you know they can be extremely frustrating.
Hypnic headaches are a rare type of headache that occurs during sleep and wakes the person up, which is why they’ve earned the nickname “alarm-clock headaches”. The pain can keep people up for at least 15 minutes, if not longer. People who experience hypnic headaches typically have them several times a week.
Hypnic headaches only occur while a person is sleeping. This timing distinguishes them from other types of headaches, such as migraines or cluster headaches, which may disturb sleep but can occur at any time of day.
Symptoms of a hypnic headache include:
The primary symptom of a hypnic headache is dull or throbbing head pain that occurs during sleep, multiple times per month, usually around the same time of night. Some people experience additional symptoms during a hypnic headache, such as nausea or sensitivity to light or sounds.
Hypnic headaches can be unilateral or bilateral, which means they can affect one or both sides of your head. However, it’s more common for a hypnic headache to affect both sides.
Hypnic headaches can range in severity, but they’re painful enough to rouse you from sleep. The majority of people describe the pain as moderate to severe.
Another distinguishing feature of hypnic headaches is the time they occur. Hypnic headaches usually occur in the middle of the night, around two to three hours after falling asleep, or between 1 a.m. and 3 a.m. They often occur around the same time and may even happen multiple times per night7. Hypnic headaches can last for 15 minutes to three hours, with an average of 90 minutes.
While hypnic headaches are rare, they’re a common experience for those who have them — occurring at least 10 times a month. Some people experience them at least every other day.
Hypnic headaches are considered a primary headache disorder, which means they are not caused by a known underlying condition. Beyond that, researchers don’t know for sure what causes hypnic headaches.
Hypnic headaches often occur during rapid eye movement (REM) sleep, so it’s possible that an area of the brain involved with processing pain gets activated, leading to a hypnic headache.
Hypnic headaches may also be linked to melatonin production. Melatonin is a hormone that makes you feel sleepy, and its production levels rise and fall throughout the day in line with your sleep-wake cycle. Because hypnic headaches occur at the same time each night, some researchers believe there may be a disturbance to the underlying rhythms that regulate melatonin production, which causes lower melatonin levels and, subsequently, hypnic headaches.
Part of the evidence supporting this theory comes from the efficacy of lithium in treating hypnic headaches, since lithium is effective in treating other chronobiological disorders and helps increase melatonin levels.
Older adults and women are more likely to get hypnic headaches, although children can also have them. Women are between 1.5 to two times more likely to have hypnic headaches than men.
Over 90% of people experience their first hypnic headache after age 50, with an average age of onset of 62 years old.
It usually takes a long time from onset of headaches to a diagnosis of hypnic headaches, which may skew the ages of those who have them to be older. On average, people don’t receive a diagnosis until seven years after their first hypnic headache.
To diagnose hypnic headaches, your doctor will inquire about your symptoms and when they occur. This will help them determine whether your symptoms are caused by hypnic headaches or another disorder that has similar symptoms. For example, high blood pressure, brain tumors, depression, and other sleep disorders like sleep apnea can also cause headaches that occur at night or wake you up from sleep.
To help rule out other conditions, your doctor may order tests such as a polysomnogram (an overnight sleep study), an MRI, or CT scans of your brain.
Caffeine is considered to be the most effective treatment for hypnic headaches. It sounds counterintuitive, but a cup of coffee can help people with hypnic headaches sleep through the night. It also has relatively minimal side effects, especially when compared with other medications for hypnic headaches, such as lithium, indomethacin, and flunarizine.
A cup of strong coffee is the recommended treatment for both preventing hypnic headaches, as well as relieving them once they have started. If your doctor diagnoses you with hypnic headaches, they may recommend drinking a cup of coffee before bed.
Caffeine pills and pain relievers containing caffeine can also be effective at relieving hypnic headaches. However, regular use can lead to medication overuse headache, a type of rebound headache caused by excessive use of medications.
After caffeine, lithium is the next recommended treatment option for preventing hypnic headaches, followed by indomethacin. Both of these drugs are effective but can have unwanted side effects. Nonsteroidal anti-inflammatory drugs (NSAIDs), opioids, and acetaminophen are not effective at relieving hypnic headaches.
Treatment prevents hypnic headaches for a majority of people. Over 40% never experience them again, even after they stop treatment.
If you find yourself regularly waking up with a headache, talk to your doctor. They can help you determine whether you have hypnic headaches and recommend a treatment plan, so you can start sleeping and feeling better.