What Causes Headaches?

Headache disorders are one of the most common brain-related conditions that people experience, with nearly 50% of adults experiencing at least one headache per year. Still, this statistic doesn’t make it any easier to live with headaches. 

Despite how many people experience headaches, the exact mechanism that causes headaches is complex. Research on headache causes remains ongoing. However, scientists generally believe a combination of neurological (brain-related), genetic, and environmental factors can lead to the onset of symptoms. 

Knowing what is causing your headaches—whether it’s biological or environmental—can help you and your healthcare provider learn how to treat your condition and reduce symptoms. 

Neurological Functioning 

There are three primary types of headache disorders: migraine, tension headaches, and cluster headaches. You can also experience a secondary headache—a type of headache that occurs as a symptom of another underlying health condition, such as a sinus infection or head injury.

Researchers have developed theories for each type of primary headache and what function (or dysfunction) in the brain could be contributing to your headache symptoms. 

Migraine 

Some research suspects that the trigeminal nerve (a part of the nervous system that sends pain and temperature signals from your face to your brain) is at fault. When your brain receives a pain signal from your trigeminal nerve, it releases proteins that cause inflammation in your brain. 

As the inflammation grows, your nerve cells become more sensitive to pain—a process known as sensitization. This process can make it easier for outside stimuli (e.g., lights or noise) to worsen the pain and extend the length of your migraine attack. ​​

Other research also suspects that an issue with serotonin (commonly known as the “feel-good” hormone) may also play a role in the activation of the trigeminal nerve. Why exactly a pain signal activates, however, is still unclear.

Tension Headaches 

Tension headaches are the most common type of headache. However, research on the exact cause remains ongoing. Some experts believe that a mechanism in the brain causes your scalp, neck, and shoulder muscles to contract—causing tension, stiffness, and pain in these parts of the body.

Other theories suggest that myofascial tissue (or, the tissue that covers your facial muscles) plays a role in the onset of tension headache symptoms. If the pain receptors on the myofascial tissue activate, your nervous system sends pain signals to your brain. Similar to migraine, this process might also lead to sensitization during a headache episode.

Cluster Headache

There are a few theories researchers have developed about the potential cause of cluster headaches. One theory suggests that an issue with the function of your hypothalamus—a part of the brain that regulates sleep, body temperature, and hormones—could cause cluster headache symptoms.

Another theory offers the idea that the release of histamine (a chemical related to allergy, injury, and inflammation) may produce accompanying symptoms of cluster headaches, such as eye redness and a stuffy nose.  

Are Headaches Hereditary?

People with close family members who experience migraine, tension, and cluster headaches are more likely to develop the condition themselves. In fact, having one or more parents with a headache disorder gives you more than a 50% chance that you will develop headaches as well. 

Research on the exact genetics of headaches is still being studied. Here’s what experts do know: in order for headaches to be passed down, you have to inherit one or more genetic mutations that make you more vulnerable to developing headaches. However, gene mutations alone don’t automatically mean you will have headaches. Environmental factors (e.g., stress) also need to be present for you to experience headaches. 

Currently, researchers have found 38 gene mutations that can make you more prone to developing headaches. As this research continues, experts may be able to find treatments that target these gene mutations and ultimately help reduce your symptoms.

Who Gets Headaches?

Some people may be more likely to develop headaches than others. These demographic factors include: 

• Sex: Those assigned female at birth are three times more likely to develop a headache disorder than those assigned male at birth.
• Age: People between the ages of 20 and 40 are most likely to experience headaches.

Risk Factors

Every person with headaches experiences the condition differently. But, certain environmental risk factors may raise your risk of developing headaches or trigger an episode if you already have a headache disorder. These risk factors include:

• Stress
• Lack of sleep or general fatigue
• Missing meals
• Eye strain
• Spending too much time on screens
• Overuse of caffeine 
• Smoking 
• Drinking alcohol
• Physical overexertion
• Exposure to bright lights 

Limiting these activities can help reduce headaches and the severity of your symptoms. 

A Quick Review

Headache is a complex neurological disorder that can cause frustrating symptoms. More than 50% of people worldwide experience at least one headache each year. However, the exact cause of the three types of primary headaches is still being researched. Experts theorize that a combination of neurological, genetic, and environmental risk factors can lead to the onset of symptoms. 

While you can alter some behaviors (e.g., alcohol intake or sleep) to reduce your risk of headaches, you can’t modify your own genetics. People with a family history of headaches, women, and adults between the ages of 20 and 40 are most likely to experience headaches. 

If you begin to notice headache symptoms or a change in your existing headache symptoms, it’s a good idea to see your healthcare provider for testing and treatment options.