“Go slower and get your form down; make sure your technique is there,” says Dr. Danan. “A headache might be coming from being out of alignment in some way.”
It’s also possible that non-gym factors play a role in your exercise headaches.
Although headaches can be caused by multiple factors, it’s helpful to focus first on common causes you can easily adjust, New York–based family practice physician and personal trainer Michele Reed, D.O., C.P.T., tells SELF.
The biggest culprit is often dehydration, she says. Some people may start to drink water once they begin exercising, but that means they could be kicking off a workout session already slightly dehydrated. Fun fact: When your brain gets dehydrated, it can actually swell a bit, and exertion can make it worse.
Fatigue is another headache trigger, and it can often pair with dehydration, especially after late nights out that involve more alcohol and less sleep than you’re used to, Dr. Reed says.
Dr. Reed says she can “almost guarantee” that working out with even a mild hangover, especially when coupled with lack of sleep, will result in a headache.
“In that case, you’re better off not exercising at all that day. Just drink a ton of water and take a nap instead,” she says.
If you are well hydrated and caught up on sleep, a headache during your workout might be brought on by stress, Dr. Reed adds. Being stressed means that you have higher cortisol levels, according to the Mayo Clinic, and since exercise can drive it up even more, that can increase your chances of getting a headache when you work out.
“Stress is very powerful in terms of the havoc it can wreak on your body and your brain, even when you’re not exercising,” says Dr. Reed. “Then you add a workout, which is basically controlled stress, and it might put you over the top.”
Here’s how to prevent exercise headaches from happening.
Pinpointing a headache cause takes time, but putting together data can help speed up the process, says Dr. Reed. She suggests keeping a small notebook handy and jotting down all the information about your workout, including nonexercise factors.
That includes how much sleep you got last night, what day of the week it is, what you ate before exercising, whether you have your period, how long into your workout you were before the headache came on, how long the headache lasted and the type of pain it was (stabbing or throbbing, for example, or just achy like a tension headache), if it’s worse with cardio versus strength training, and any strategies you tried to make it better, such as drinking extra water for a few hours pre-exercise. That way, Dr. Reed advises, you can start to change the variables.
For example, if cardio during your period is a headache trigger, maybe you switch to strength training that week instead. If circuit workouts cause the pain, cut your work time—and increase your rest—to see if that works better.
Notice pain comes on when you skimp on fluid beforehand? Be sure not to ignore your thirst—thirst is a simple rule to hydrate enough. The American College of Sports Medicine also recommends consuming 16 to 20 ounces of fluid at least four hours before exercise, and to drink when you’re thirsty during your workout.
Then, take a look at how you started your workout: Did you go right into the good stuff and skip the warm-up? That can be a problem, since you’d be risking that sudden blood vessel dilation in your head, says Dr. Danan. Warming up allows that process to happen more gradually, as you increase blood flow to the muscles and get your circulation ramping up. So make sure you take the time to warm up for at least five to 10 minutes with a focus on dynamic stretches—which means that you’re moving as you stretch. For example, if you’re going to run, jog in place for a few minutes and then do walking lunges for a few minutes after that.