What Causes Chronic Migraine?

Migraines are intense headaches that can cause pain, fatigue, nausea, light flashes, and other physical symptoms. When they are chronic—recurring and existing for extended periods—they can shut down your life as you close yourself up into a quiet, dark, and cool cocoon.

Migraines are miserable, and for some people, they happen regularly—more than twice a week, or 15 headache days a month, with at least eight of those having migrainous features.

But why do some people experience chronic migraine? Here's what you need to know about what causes chronic migraine and some of the most common triggers for those painful symptoms.

What Causes Chronic Migraine?

Unfortunately, it's not entirely clear what causes chronic migraines—or migraines, in general. However, chronic migraine has some common but treatable risk factors, including:

• Depression and anxiety
• Chronic pain disorders
• Obesity
• Asthma
• Snoring
• Stressful life events
• Head or neck injury
• Caffeine
• Acute medication overuse
• Persistent, frequent nausea

Other conditions, like vascular malformations or brain injuries, can look identical to migraines, Robert Cowan, MD, professor of neurology and chief of the division of headache medicine at Stanford University, told Health. But those fall under a different umbrella ("secondary headache") than migraines.

Who's at Risk for Chronic Migraine?

Some people are more likely than others to develop chronic migraines. While some risk factors are adjustable, others you cannot change, such as:

• Family history: If one or both of your parents has migraines, you have a 50% to 75% chance of developing them.
• Age: Migraines can start at any age and as young as adolescence. Migraines often begin at puberty and affect those aged between 35–45.
• Sex: Women are three times more likely than men to get migraines.
• Certain medical conditions: Individuals who experience depression, anxiety, obesity, and snoring, among several conditions, may have a greater likelihood of having migraine episodes that can lead to chronic migraines.

What Triggers a Chronic Migraine?

While the cause of migraines isn't totally clear, researchers have gained a better understanding of what happens when migraines start to become chronic. 

A migraine "is a problem with how you interpret sensory stimuli from your body and from the environment," explained Dr. Cowan. "Your brain starts to adapt. It lowers its pain threshold. It's almost like when you hear a sound in the night. Suddenly, your senses seem to be heightened."

Various lifestyle and environmental factors, known as "triggers," can set off a migraine episode.

"Triggers are very real for some people," Mason Dyess, DO, a general neurology and headache medicine physician at Ochsner Medical Center, told Health. But the better you're managing your migraines, the less you have to worry about triggers, said Dr. Dyess. Strategies may include working with a healthcare provider on preventive strategies and pain management when a migraine strikes.

"Traditionally, the better controlled your headaches are, the fewer you have per month. And the faster you can stop them, the less sensitive you are to triggers," added Dr. Dyess.

Until your migraines are under control, "if you know something's going to give you a migraine, avoid it, especially until we get a strong preventive and acute regimen in place for you," noted Dr. Dyess.

Here's what you should know about some of the most common triggers of chronic migraines.

Change in Sleep

Sleep renews and repairs all parts of the body—including the brain. You are more prone to migraine attacks when something disrupts your sleep schedule. 

Sleep loss and oversleeping are common headache triggers. People living with migraine are between two and eight times more likely to experience sleep disorders than the general public. 

How to reduce risk: Making sleep changes such as establishing consistent sleep and wake-up times can help encourage restful, regular sleep and reduce headaches. Also, getting between seven and eight hours of sleep per day is essential. Experts also recommend avoiding substances that interfere with sleep, such as caffeine, nicotine, and alcohol.

Change in Physical Activity

A change in your physical activity status, perhaps a sudden intense workout, can trigger a migraine.

In one study published in 2013 in the Journal of Headache and Pain, researchers found that of 103 people with chronic migraines, 38% experienced migraines because of exercise. Of those people, more than half stopped their exercises to reduce or eliminate migraine attacks.

Whether your rigorous exercise triggers a migraine depends on how active you usually are. For example, if you're not much of a runner and you decide to tackle a half-marathon, that can be a trigger, explained Dr. Cowan.

How to reduce risk: If you have a history of exercise-induced migraines, try to avoid exercise that requires great or sudden physical exertion. Opt for exercise that is easier on the body, like yoga or walking.

Change in Eating Patterns

Missing meals and fasting have long been reported as headache triggers. 

One study published in 2014 in the Journal of Clinical Neuroscience reported that not eating caused headaches in 57% of people with migraines. The research ranked eating habits alongside stress, hormones, and sleep disturbance as the most common and consistent migraine triggers.

"Not so much what you eat but when you eat," said Dr. Cowan. "Skipped meals are a big trigger. Overeating can be a big trigger."

The researchers of the 2014 study also found that eating behaviors affect headaches. Nighttime snacking reduced the odds of experiencing a headache by 40% compared to having no food.

How to reduce risk: Following a regular eating schedule and possibly snacking at night could help keep this migraine trigger at bay.

Stress

Stress is a trigger for almost 70% of people with migraine. Unfortunately, stress and migraine feed into a vicious and painful cycle. Stress can cause migraine. Chronic pain creates more stress. And the cycle continues.

"Anything can be stressful," said Dr. Cowan. Too much screen time, a pet pooping where they're not supposed to, an argument with your spouse. But unfortunately, stress can set off a migraine.

How to reduce risk: Trying to manage your stress level is important for eliminating the trigger. The American Migraine Foundation recommends that biofeedback, relaxation therapy, meditation, exercise, and a consistent sleep schedule be extremely helpful.

Loud Sounds, Strong Scents, or Bright Light

"If I walk into the wrong entrance of Nordstrom through the perfume counters, I'll never make it to the men's section. I'll have a headache that quickly," explained Dr. Cowan. For others, that might be a particularly loud noise or a bright room.

Indeed, a common symptom of migraine is osmophobia, an aversion to odors. For people with osmophobia, some odors may activate nerve receptors in the nasal passages that may trigger a migraine attack or aggravate one that has already started.

Additionally, natural light can also be a strong trigger of migraines. The condition is called photophobia, one of the criteria for diagnosing migraine.

How to reduce risk: If odor or light is your migraine trigger, your best approach is to avoid both as best as possible. Don't be afraid to ask family members or coworkers to refrain from wearing perfume or cologne. Wear sunglasses, avoid bright lights, and avoid flickering lights.

Medication Overuse

If you're constantly taking medications to relieve migraine pain, you may be setting yourself up for additional headaches. So-called medication overuse headaches, or rebound headaches, result from frequent use of over-the-counter (OTC) pain relievers and certain acute migraine medicines.

Medication overuse headaches are experienced more than 15 days a month for at least three months. Those headaches get much worse during medication overuse. The risk of medication-overuse headache is most common with narcotic- and butalbital-containing medications.

How to reduce risk: If you are experiencing medication overuse migraines, consult a healthcare provider. They can make recommendations for pain management.

Poor Posture

"When you're tensing the neck muscles, which is what happens with bad posture, you're irritating trigeminal nerves, as well. And that's what sets up the tension," said Dr. Cowan.

Long periods of sitting and increased time using technology can negatively impact posture, neck pain, and headaches, including migraines.

How to reduce risk: To avoid migraines triggered by poor posture, make sure you take breaks when you are sitting for extended periods to do some stretching exercises.

Make sure you practice good seated posture, including:

• Sit with your head and neck upright in a neutral position.
• Rest your feet flat on the floor (or supported by a footrest), and avoid sitting on your feet or crossing your legs. 
• Keep your arms and elbows close to your body, use an armrest for support, and keep your wrists in a neutral position.
• Sit with your hips fully back in your chair and with your back supported.
• Try placing a small rolled towel behind your lower back to decrease the space between the chair and your back.

Caffeine and Alcohol

If you're a regular caffeine drinker and miss your morning cup, that can bring on a migraine, said Dr. Cowan. However, while many people find that too much caffeine triggers a migraine, others say a cup of coffee can stop their symptoms. In fact, caffeine is an ingredient in some migraine medications.

Alcohol is a trigger for many people with migraines, too. Although red wine and beer are the principal alcoholic migraine trigger, other types of alcohol can also trigger migraines.

How to reduce risk: If caffeine or alcohol are triggers of migraines, limit your consumption of either or both. If you are experiencing the warning signs and symptoms of a migraine attack after drinking caffeine or alcohol, take your medication immediately.

Certain Foods and Food Additives

Food triggers are entirely dependent on the person. Food migraine triggers include:

• Chocolate
• Aged cheese
• Cured meats
• Smoked fish
• Yeast extract
• Food preservatives that contain nitrates and nitrites, artificial sweeteners, monosodium glutamate (MSG)
• Anything with a strong smell

How to reduce risk: If you can identify specific food triggers, avoid those foods as much as possible. You can also adopt a migraine diet that eliminates foods and ingredients known to trigger migraine.

Dehydration

Some people with migraine pain find that becoming parched can lead to another migraine.

Even the slightest hint of dehydration can lead to debilitating head pain for some people. Dehydration affects the body on all levels and can cause dizziness and confusion and even become a medical emergency.

How to reduce risk: Stay hydrated. Keep on top of your hydration levels by carrying a water bottle and regularly drinking throughout the day.

Hormone Changes

Up to 75% of women experience menstrual migraines, which occur only during periods. Changes in levels of the hormones estrogen and progesterone cause those migraines.

How to reduce your risk: Paying attention to lifestyle habits, such as adequate sleep, stress reduction, and balanced, regular meals, can help keep up with menstrual migraines. Having healthy snacks between meals and drinking plenty of water keeps your brain hydrated.

Weather Changes

Many people with migraines say their headaches come on when the humidity changes, during storms, excessive heat, or in extremely dry conditions. 

For most of those people, what's bothering them is "a change in barometric pressure," said Dr. Cowan. "Your eyeballs are actually your barometric monitor. That's where the brain perceives changes in barometric pressure and also in the tympanic membrane in the ear."

How to reduce risk: If you know that weather changes trigger your migraines, stay indoors as much as possible when the conditions trigger you.

A Quick Review

Triggers for chronic migraines vary among individuals. Lifestyle habits, the weather, hormones, diet, and even posture are among the triggers that cause debilitating pain in some people with migraines.

All of those triggers have something in common. "People with migraines like things steady and predictable," said Dr. Cowan. "When you vary from those patterns, your brain thinks there's something wrong."