People may develop a headache after exercising for a variety of reasons. Dehydration, exercising in heat or at high altitudes, or muscle tension can all lead to headaches after exercise.
In some cases, an underlying condition could be causing a headache after exercising. In this article, we look at possible causes of a headache after exercise, treatment options, and when to see a doctor.
A primary exertional headache is a headache that people get solely from exercising and has no underlying causes.
Symptoms of primary exertional headache include:
- pain, usually on both sides of the head
- a pulsating sensation
The pain can last between 5 minutes to 48 hours and may feel similar to a migraine.
People may be more likely to get a primary exertional headache after exercising in hot conditions or at a high altitude.
A secondary exertional headache occurs because of an underlying condition, such as:
- heart disease
- stroke, or bleeding in the brain
- a tear in an artery
- reversible cerebral vasoconstriction syndrome, which is a narrowing of the blood vessels
- a brain tumor or lesion
If people do not replace fluids during or after exercise, they may become dehydrated. Water and electrolytes keep the body hydrated, and people lose both of these through sweating.
When a person is dehydrated, they may develop a headacheTrusted Source.
Other symptoms that may indicate dehydration include:
- feeling thirsty
- feeling lethargic or fatigued
- dark yellow urine
- producing less urine than usual
- dry mouth or lips
- feeling irritable
Learn more about dehydration headaches.
A tension headache is the most common type of headache. Muscle tension from exercising or incorrect posture during exercise can cause these headaches. People who experience stress may also develop tension headaches.
Symptoms of a tension headache include:
- mild to moderate pain
- a gradual start to the headache
- pain in the neck and back of the head
- pain that can be either a dull ache or a vice-like band around the head
- pain that often affects both sides of the head
- usually constant pain rather than throbbing
Learn more about tension headaches.
Exercising in heat
Exercising in a hot climate or direct sunlight can trigger a headache and migraine. Increased heat levels can cause excess sweating, which can lead to dehydration.
Bright sunlight may also act as a trigger for headaches and migraines.
Low blood sugar
If people do not eat before exercising, they may develop a headache due to low blood sugar levels. Exercise burns calories, and if people do not take in enough calories before exercising, their blood sugar levels can drop.
When people eat carbohydrates, the body converts them into glucose. The brain, in particular, relies on a constant supply of glucose to function properly. If the brain does not get enough glucose, it can cause a variety of symptoms, including headaches.
Other symptoms of low blood sugar levels can include:
- feeling faint or dizzy
According to The Migraine Trust, moderate, regular exercise may help prevent migraines and reduce the severity of symptoms.
However, exercise may be a trigger for migraines in some people. Some of the most common symptoms of migraine include:
- throbbing head pain
- increased sensitivity to light and sound
If exercise does trigger a migraine, there may be underlying reasons, such as:
- starting exercise abruptly, so the body requires a sudden increase in oxygen
- low blood sugar
- lifestyle changes, such as diet