A heat headache can occur when the weather is hot or during physical activities that raise the body temperature. Treatments and preventive steps such as drinking liquids and avoiding sun exposure may help.

Heat headaches are unlikely to result from the heat itself. In most cases, the cause is another trigger associated with heat, such as dehydration, too much sun, or heat exhaustion.

This article discusses the causes of heat headaches, other symptoms, treatment options, and more.

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The following are some common triggers of headaches in warmer temperatures:

Dehydration

Rather than the heat itself, a likely cause of heat-related headaches may actually be loss of fluids, as dehydration can cause headaches.

Dehydration triggers a headache because a lack of liquids leads to the constriction of blood vessels. In hot weather or during exercise, the body loses water and electrolytes through sweat. If a person does not replace these fluids, dehydration can occur.

Dehydration may also worsen existing conditions, such as migraine, and their related symptoms.

Heat-related illnesses

Heat-related illnesses, such as heatstroke and heat exhaustion, are common during warmer months. A headache is a common symptom.

To prevent heat-related illnesses, a person can limit their time in hot environments and avoid excessive exercise in the heat.

Other headache triggers

Several environmental and lifestyle triggers can potentially cause a headache or migraine to occur.

According to the National Institutes of Health (NIH), other common headache causes include:

  • too much sun or light
  • dehydration from not drinking enough
  • not getting enough sleep
  • alcohol use
  • bad posture

Heat or environmental headaches may present different symptoms depending on what is causing them.

Heat exhaustion

If heat exhaustion is the cause of a headache, a person may experience additional symptoms relating to overheating.

According to the Centers for Disease Control and Prevention (CDC), the following are some warning signs of heat exhaustion:

Heatstroke

Heatstroke has similar symptoms to heat exhaustion, but it is more serious. A person should call 911 if someone experiences the following symptoms:

Dehydration

In addition to headaches, dehydration can cause other symptoms, including:

Without proper treatment, dehydration can become severe. A person should call 911 if they experience any of the following symptoms:

  • confusion
  • not urinating at all
  • fainting
  • fast heartbeat
  • fast breathing
  • shock

Migraine

People with migraine often experience other symptoms in addition to severe pain in the head.

According to the Office on Women’s Health, symptoms of migraine can include:

People can take steps to prevent and treat headaches due to heat, dehydration, or other environmental triggers.

The CDC advises people to take steps to prevent heat-related illnesses when enjoying warmer temperatures. These include:

  • Staying cool: If a person is spending time outside in the heat, they should stay in the shade as much as possible, take frequent breaks, and limit outdoor activities to cooler parts of the day. Using air conditioning and fans indoors can also help.
  • Staying hydrated: It is a good idea to carry a water bottle to drink from and refill it throughout the day. Limiting drinks high in sugars, sodium, caffeine, and alcohol is best, as these beverages can increase headaches and reduce hydration.
  • Be aware of symptoms: As soon as a person feels symptoms of heat-related illness, such as fatigue, headache, or dizziness, they should rest in a cool place immediately. They also need to take steps to cool down, such as drinking cold water and taking a cool bath.

If a person has a headache, some self-care techniques may help reduce or eliminate the pain. These include:

  • Medication: A person can take over-the-counter (OTC) pain relievers, such as ibuprofen or acetaminophen, as necessary. Long-term use of pain relievers can worsen headaches, so it is a good idea to consult a doctor for a treatment plan for chronic headaches.
  • Cooling down and hydrating: Taking steps to cool down and hydrate can help ease headaches due to heat-related illnesses and dehydration.
  • Lifestyle changes: Getting enough sleep, following a nutritious diet, adjusting posture, and managing stress can help relieve headaches.
  • Rest: Resting in a cool, dark room with the eyes closed can sometimes ease a headache relating to hot weather and light exposure.

If a person experiences frequent headaches, they need to contact a doctor. Frequent headaches may be a sign of an underlying health condition.

If a person experiences a migraine headache for the first time or notices any changes in their frequency, they need to seek medical attention.

When a person displays symptoms of heatstroke, someone with them should contact 911 right away. Symptoms to watch for include:

  • confusion
  • weakness
  • dizziness

In most cases, if a person removes themselves from the heat or drinks more fluids, their headache will go away in time. OTC pain relievers and rest can help ease the pain.

People living with migraine need to talk with a healthcare professional about treatment strategies. These approaches often focus on both treating the migraine and helping prevent future migraine from occurring.

If heat, sun, or other environmental factors are new triggers, a person needs to talk with a doctor about additional strategies to prevent future migraine headaches.

A person may develop a heat headache when they experience triggers, such as overheating, dehydration, or other environmental factors. The same factors can also trigger migraine headaches.

When a person takes precautions, such as drinking more liquids and avoiding strenuous exercise in hot conditions, they may prevent the onset of a headache.

If a headache or migraine occurs, a person needs to drink more fluids, move to a cooler place, and take a break from activities that may be raising their body temperature.