What are exertional headaches (also known as exercise headaches)?

Exertional headaches differ from other types of headaches in that they are triggered by physical activity.

In sports medicine and research literature, “exertional headache” is recognized as a distinct condition, says Colin Tomes, PhD, PT, assistant clinical professor of health sciences at Moravian University in Bethlehem, Pennsylvania. “This term is crucial because headaches can occur during physical exertion that arise from another cause, which may be a cause for concern.”

That said, the physical event that triggers an exertional headache can vary. It could be anything from running to gardening to having sex, he says Klee Bethel, MDinterventional pain anesthesiologist at the Neil Riordan Center for Regenerative Medicine in Tempe, Arizona.

It is unclear why exertional headaches occur in some people and under some circumstances, but not others. One theory is that strenuous exercise dilates (widens) the blood vessels in the skull. When this reaches a certain threshold, palpitations and pain can occur.

However, regardless of the exact mechanism, certain factors increase the likelihood of experiencing an exertional headache. They include:

Exercise

An exertional headache is usually the result of overexerting yourself during exercise. The combination of dehydration (more on this shortly), pressure inside the skull, and muscle tension resulting from intense or prolonged exercise can create a perfect headache storm, says Dr. Chen. The high-impact nature of running makes it particularly likely to cause headaches, he adds.

Dehydration

Lack of fluids can significantly contribute to exertional headaches, especially when exercising outdoors or in high temperatures. “Low fluid levels thicken the blood and tighten blood vessels, reducing the delivery of nutrients and oxygen and potentially causing headaches,” says Dr. Tomes.

too much sun

Overexposure to the sun is a risk factor for heat exhaustion, which often manifests as a headache.

Exercising in sunny conditions can make you more likely to sweat a lot, causing dehydration which can lead to a headache.

Tomes recommends gradually increasing outdoor exercise to slowly acclimate to the heat.

low blood sugar

One of the benefits of exercise is that it can help lower blood sugar for up to 24 hours.

For most people, that’s a good thing. However, for people with existing blood sugar problems, low blood sugar could cause a headache, says Dr. Bethel.

One study, for example, found that some types of migraine, which often cause headaches, can occur when the brain cannot use glucose (sugar) effectively.

If you tend to have low blood sugar, you may be at higher risk for exertional headaches.

Bad form of exercise

Headaches after running, cycling, or strength training could indicate a problem with your body mechanics. When your exercise technique is not proper, it places excessive stress on your muscles and joints, resulting in strain.

“Muscle tension, particularly in the neck and shoulders due to poor posture or overexertion, can compress nerves and blood vessels, contributing to headaches during physical activity,” says Chen.

Underlying health conditions

Not all exertional headaches are as simple as they seem. “Some headaches are secondary to health problems, such as blood vessel problems, heart disease, and structural brain injuries,” says Tomes.

For example, reduced blood flow to the brain caused by heart or blood vessel problems could predispose you to headaches. Meanwhile, brain injuries caused by neurological conditions such as multiple sclerosis are known to cause headaches even without physical exertion.

See your primary care provider if your symptoms are new or if you suspect your exercise headaches have an underlying cause.