Having a headache is a pain—literally and figuratively. And it’s even worse when your headaches feel constant and as if pain is nagging you all the damn time. You might be surprised to learn that there’s a fairly lengthy list of causes of constant headaches. Some reasons behind chronic headaches are not serious, while other causes can signify a deeper health issue is at play.
What causes a headache?
Experts don't completely understand what's happening in our skulls when a headache hits, but the most likely explanation is that something causes the blood vessels to swell, subsequently stretching the nerves around them and firing off pain signals.
There are three primary types of headaches: migraines, tension, and cluster, Susan Hutchinson, M.D., director of Orange County Migraine & Headache Center, tells SELF. Here’s a quick summary of each type:
Cluster headaches: This type occurs usually on one side of the head, causes one eye to tear, and leaves you feeling extremely agitated. They are not very common and seem to run in families, Dr. Hutchinson says. An “attack” may last weeks or months, according to the Mayo Clinic.
The cause is unknown, but cluster headaches may occur if something with the body’s biological clock is off, per the Mayo Clinic. Also, cluster headaches generally aren’t triggered by certain factors, like stress or hormonal changes, the way tension headaches and migraines can be. (The exceptions: Certain medications and alcohol may trigger cluster headaches, per the Mayo Clinic.)
Migraines: Migraines typically cause pain (sometimes so intense that it affects a person’s ability to function) on one side of the head and possibly nausea and/or sensitivity to light, the Mayo Clinic explains.
It’s not totally clear what causes migraines, but it’s possible that they have to do with “changes in the brainstem and its interactions with the trigeminal nerve,” the Mayo Clinic says. (Changes in serotonin levels in the brain may also play a role, but more research is needed to determine how and why.) Experts believe migraines are primarily genetic.
Tension headaches: Anyone can get a tension headache, which is caused by muscle tightness in the head, neck, or scalp, according to MedlinePlus. "Unlike migraines, which we think are genetically predisposed, tension headaches are pretty universal," Dr. Hutchinson says.
Tension headaches can be caused by everything from dehydration and workplace stress to undiagnosed diabetes or an autoimmune disease. A tension headache feels tight, like your head is in a vice, and can occur on both sides and commonly hits later in the day as tension builds. "It's a tight, oppressing feeling," Dr. Hutchinson explains.
If you're experiencing constant headaches, chances are they're either tension or migraines.
So what does it mean if your headaches are constant or chronic?
Technically, for your headaches to be considered chronic, they need to go on for 15 days or longer per month, for at least three consecutive months, SELF reported previously. That being said, if you have recurring headaches for, say, two weeks, that doesn’t mean you should discount your pain—you should still see your doctor.
The causes of constant, headaches—whether tension or migraine—range from totally minor to pretty major. Here are 10 things your headaches could reveal about your health.
1. You're stressed.
"Unresolved stress can really contribute to headache," Dr. Hutchinson says. As mentioned, tension headaches happen when the muscles of the neck and scalp tense up, and this can be a physical response that your body has to stress and anxiety, MedlinePlus explains.
Fix it: This is where stress management and self-care techniques become crucial—and possibly therapy. Psychotherapeutic interventions like cognitive behavioral therapy can help you better cope with anxious thoughts. Everyone’s stress and anxiety management methods are different, as SELF reported previously; but oftentimes a mix of techniques that you can do on your own and/or with a mental health professional is best.
2. You're dehydrated.
"With any kind of headache, a person needs to look at their health habits," Dr. Hutchinson says. One important thing to look at is water intake, as dehydration can cause headaches. The exact connection is unknown, but experts believe it has to do with the way blood volume drops when you're not getting enough water. Lower blood volume means less oxygen is getting to the brain.
Fix it: Keep an eye out for obvious signs of dehydration, including having yellow pee, feeling thirsty, and having a dry mouth. Then, drink more water (of course). You can also up the amount of foods with high-water content in your diet (think: celery, watermelon, and tomatoes).
The amount of fluids you need to consume depends on different factors, like your age and physical activity levels. But as a general rule of thumb, women should consume about 2.7 liters (91 ounces) of water (from drinks and food) each day, and roughly 3.7 liters (125 ounces) of water daily for men, according to the National Academies of Sciences, Engineering, and Medicine.
3. You're anemic.
Anemia is a condition where you lack enough red blood cells to properly transport oxygen to tissues throughout your body, the Mayo Clinic explains. It can bring on symptoms including fatigue, feeling weak, shortness of breath, and others. "More severe anemia can cause headache," Dr. Hutchinson says.
There are different causes of anemia, including having an iron deficiency, having lower-than-normal levels of B-12 and/or folic acid, or having a chronic health condition that leads to anemia.
Fix it: If you’re having symptoms of anemia, bring them up with your doctor. From there, they may decide to test your red blood cell levels to determine whether you are anemic (or they may choose to do other tests or examinations to rule out other possible underlying health conditions).
Luckily, if you suffer from iron- or vitamin-deficiency anemia, it's reversible by upping iron or vitamin intake. Your doctor will guide this course of treatment.
4. You have a chronic disease.
Fix it: If you have chronic headaches, it's always worth talking to your doctor if anything feels off with your body to figure out if an underlying condition could be causing your issues. Even if you’re unsure and think it may be something minor, don’t delay seeking medical attention and be your own health advocate.
5. You’re dealing with hormonal issues, like menstruation.
Thanks to the drop in estrogen right before menstruation, many women experience PMS-related headaches. In fact, menstruation is one of the biggest migraine triggers for women.
But it's not the only time a change in estrogen levels can cause a headache—both perimenopause and postpartum periods are marked by a significant drop in estrogen, and as a result, often come with headaches. Pregnancy, too, affects estrogen levels, so you may notice that your headaches worsen (or disappear in some cases) during this time, the Mayo Clinic says. "Any time of hormonal change is a vulnerable time for headaches," Dr. Hutchinson says.
Fix it: If you notice that your headaches appear to be cyclical and coincide with your period, it’s worth bringing this up with your doctor, who may suggest going on hormonal birth control or switching your current birth control.
As the Mayo Clinic explains, hormonal birth control can have an effect on your headache patterns; and for some people, hormonal contraception may make headaches less frequent and intense because they reduce the drop in estrogen that happens during your menstrual cycle.
For short-term headache relief around your period, typical headache remedies can help, like using ice or a cold compress, practicing relaxation techniques, or taking an over-the-counter pain relief medication.
It’s worth noting that if you’re dealing with chronic headaches during pregnancy, you should consult your doctor first about what solutions make sense for you, as some headache medications are not safe for pregnant people, the Mayo Clinic says.
6. You have a sinus problem.
Sinus headaches are not that common, Dr. Hutchinson notes. "Most sinus headaches are just migraines with sinus symptoms," she says. So if you have recurrent headaches in your sinus or facial area, chances are it's a migraine. In fact, studies have shown that approximately 90 percent of people who see a doctor for sinus headaches are found to actually have migraines, according to the Mayo Clinic.
But if your headache is paired with fever, phlegm, or any other indication you might be sick, an underlying sinus infection may be to blame.
Fix it: If you do have a sinus infection, the headache should go away after taking antibiotics to knock out the infection—so pay a visit to your physician.
7. Your body clock is off.
Ever wake up for a super early flight and notice a nagging pain in your head? Disrupting your body's schedule can trigger headaches, Dr. Hutchinson says.
Getting up earlier (or later) than usual can throw off your circadian rhythm. "Travel in general is a trigger," she adds. The stress of traveling, change in barometric pressure, change in time zones, and just being at an airport can all trigger a headache.
Fix it: While sometimes it’s just not possible to maintain the exact same sleep-wake schedule (say, if you’re traveling abroad), it’s important to try to keep as close to your typical routine as possible. This way, you’ll limit the disruption to your body clock, and in turn, keep headaches away, or at least more infrequent.
Also, stress relief practices are especially important in hectic travel settings—like loud, crowded airports—to keep nagging head pain under control.
8. You drink too much caffeine.
Caffeine causes vasoconstriction in your blood vessels, meaning they get a little narrower. If you drink coffee or other caffeinated drinks every day, your body gets used to it, Dr. Hutchinson explains. So when you skip it one day, your blood vessels don't become constricted and can make your head hurt. It becomes a vicious cycle, slugging back a mug to find relief, and just further deepening your need for caffeine.
Fix it: "It's unrealistic to tell all headache patients to avoid caffeine," Dr. Hutchinson says. She recommends moderation—a maximum of two caffeinated drinks in one day—to avoid that withdrawal headache when you go without. (Keep in mind, that means two small-size coffees, not jumbo cups.)
9. You're taking too many headache meds.
Headache treatments can potentially backfire. "Sometimes, the thing you’re taking for headache starts working against you," Dr. Hutchinson says. Overdoing it on painkillers can actually make the pain worse—and the caffeine in some medications like Excedrin can cause withdrawal headaches, compounding the effects. Overuse of any pain medication to treat headaches can cause what's called a rebound headache.
Fix it: If you've been taking a lot of OTC medications, try stopping for a day or drastically limiting your intake. "If you're able to then have a day without a headache and don’t need to take anything, then you can say you’re out of the rebound," says Dr. Hutchinson.
10. In rare cases, constant headaches could be a sign of a brain tumor.
Googling your headache symptoms may result in a self-diagnosis of brain tumor. Rest assured: They're rare, so chances are you don't have one. But it’s a possibility, and something you don't want to miss, Dr. Hutchinson says. "If a patient’s had a regular headache pattern [for months] and it hasn’t changed, it's usually not a red flag," she says.
If headaches are a new thing for you, are the most severe you've ever experienced, or are changing or worsening over time, these are signs your doctor may order a brain scan. But if you're ever worried about what's causing your headaches, it's worth discussing with your doctor.