You should finish a run with a runner’s high—not a throbbing head. But getting headaches after a workout isn’t uncommon.
They’re called exertional headaches, explains Steven E. Mayer, M.D., a sports medicine physician at Northwestern Medicine Central DuPage Hospital. “Exertional headaches are headaches that are provoked by any type of physical activity,” he says. “They’re more common with strenuous physical activities versus light activities, and running is certainly considered a more strenuous type of activity.”
Obviously, there are a lot of things that can cause headaches; exertional headaches are classified as such because they’re specifically tied to exercise versus other triggers like staring at a screen, grinding your teeth, or more serious disorders like inflammation, infections, or injury.
“Research shows that these headaches present with more of a pulsating feeling rather than a painful sharp pain,” says Joanne Donoghue, Ph.D., an exercise physiologist and director of clinical research at NYIT College of Osteopathic Medicine. “However, they can become so uncomfortable that activity may have to be discontinued while occurring.” Aside from that throbbing sensation, they may also come with side effects like nausea, vomiting, double vision, and stiffness in the neck, she adds.
Workout-induced headaches could be caused by changes in your blood flow—you know that feeling, when your blood is pumping hard on a great run. “When we exercise, our body responds by vasoconstriction of blood flow to certain parts of our body and vasodilation of blood flow to other parts that require it most,” explains Donoghue. In layman’s speak, that means parts of your body get more blood than others. “Most of the blood is redistributed to working muscles, although there could be up to a 25 percent increase in cerebral blood flow as well.” But scientists aren’t exactly sure of the cause and effect relationship here yet.
One definite culprit for an exercise-induced headache could be dehydration. When you’re dehydrated—i.e. your body is losing more fluid than it’s taking in—your blood volume decreases, “which essentially decreases the amount of blood flowing through the brain; in turn, that can limit how much oxygen is delivered to the brain,” explains Mayer. “The brain can actually shrink slightly from that volume loss, and it’s thought that these above issues are what can potentially lead to headaches.”
It’s important to head into a long run or race properly hydrated, especially considering the fact that by the time you feel thirst, you’re already dehydrated. Give yourself the pee test before your workout: Your urine should be pale yellow; dark yellow urine, especially with low volume, indicates relative dehydration, Mayer says. That doesn’t mean you have to drink eight cups of water; rather, the National Academies of Sciences suggests women consume a total of approximately 91 ounces of water and men 125 ounces collectively from beverages and food each day.
Hydration goes hand in hand with your electrolyte levels. Most runners are aware of the important role electrolytes play in performance—and imbalances can lead to headaches during and after running. “The most common cause is hyponatremia, or low sodium,” says Mayer. “This is usually secondary to ingesting too much water as a runner drinks liquids throughout their exercise, which can cause swelling in the brain and can lead to headaches (and sometimes even more serious issues such as seizures or even coma).”
Luckily, it’s pretty easy to avoid electrolyte imbalances before a high-intensity run. “If you’re exercising longer than an hour, consuming electrolytes an hour beforehand and then every 15 to 20 minutes while you are running can help,” says Donoghue. “This can be done through liquid gels, capsules, or fluids containing electrolytes.”
Headaches are also tied to your blood sugar levels. Since glucose, or blood sugar, is one of your body’s main energy sources, not having enough of it can trigger headaches. Insulin controls your body’s blood sugar levels, and “low insulin levels can lead to changes in your catecholamines—hormones such as dopamine, epinephrine (adrenaline), and norepinephrine, which are produced by the adrenal glands—that can influence how the brain behaves,” says Donoghue. In other words, with less blood sugar, there’s less to fuel the brain, says Mayer.
Having a balanced snack 30 minutes before exercise can avoid a drop in insulin, and “taking in carbohydrates in the days before a long run or race helps with prevention,” says Mayer. Not to mention, “you should always have a nutrition plan in place for the run,” he adds. “There are plenty of over-the-counter products that include sugars and are easy for runners to carry.”
Even your running form could be causing headache pain. “Poor running form can cause overuse injuries due to an unbalanced force being applied repeatedly over a prolonged period of time,” says Donoghue. As that force travels up your kinetic chain, it can definitely cause headaches—especially if it’s related to tension in your neck and shoulders. Foam rolling or regular massage can help ease tension in that area.
And, of course, there are external conditions that can trigger a headache or exacerbate any of the issues above. “In hot and/or humid weather, runners do need to pay more attention to their hydration and electrolyte status,” says Mayer. “Things can quickly go downhill without a plan.” Hydrating properly and making sure you have enough fuel can make all the difference between going home with a runner’s high or holding your head in your hands.
Most of the time, exertional headaches are completely benign and shouldn’t stress you out, says Mayer—they should go away with a little rest and maybe OTC meds. “But if it is a headache that is sustained and does not seem to go away with rest, or if it’s repetitively causing an issue without resolution, then I would recommend seeing a physician with experience in evaluating and treating headaches,” he says.