The Real Reason You Get A Headache After Going On A Run

You might expect your calves or thighs to ache from running, and hill work can be a pain in the butt — literally. Sore feet? Also par for the (training) course, especially if you're overdue for some new sneakers. Even some tightness in other parts of your body is to be expected: your arms had to slice the air from side to side to keep up your pace, and if you had proper form, your core was engaged. But why on earth would you get a headache after a run? Your head would seem to be the only part of your body that wasn't involved in your workout! In fact, though, many runners will experience a throbbing sensation on one side of the head or pain throughout their entire head (via Healthline). 

There likely are more possible explanations for a runner's headache than there were miles on your path. If you ran with a lot of tension in your shoulders and neck, that can certainly lead to a headache, for example, and bright sunlight can be a headache trigger for many people (via Verywell Health). If the pain was especially sharp and sudden, though, something called an exertion headache may be to blame. "Exercising in hot, humid conditions or at high altitudes when your body isn't acclimated yet," can bring on exertion headaches, Clifford Stark, DO, sports medicine specialist in New York City, explained to Health. Exertion headaches can last for as little as a few minutes to up to 48 hours.

Another very common cause of a headache after a run is dehydration, which means you're outputting more fluids (aka sweating) than you're taking in (aka drinking). This "... essentially decreases the amount of blood flowing through the brain; in turn, that can limit how much oxygen is delivered to the brain," Steven E. Mayer, M.D., a sports medicine physician at Northwestern Medicine Central DuPage Hospital, explained to Runner's World. And that can hurt! "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," Mayer added. Drinking more water can prevent these headaches — get in a good guzzle before and after your run, and carry some water with you if you plan to exercise for more than 30 minutes.

Just as not drinking enough can cause headaches, so, too, can not eating enough. If you're running on empty, your blood sugar may be too low, which can result in dizziness, irritability, sweating, and yep, you guessed it, a headache (via University of Michigan Medicine). To avoid a headache from low sugar — not to mention all of the other unpleasantness that comes from improper fueling — your best bet is to have a small snack up to two hours before your run, and then a recovery meal that has a 4:1 ratio of carbohydrates to protein (via Active).