Overview
Heatstroke happens when the body becomes dangerously overheated and can no longer cool itself effectively. It may follow exposure to very hot weather, intense physical activity, or both. Heatstroke is more serious than heat exhaustion and can quickly become life-threatening.
Key Symptoms
Warning signs can include a very high body temperature, confusion, slurred speech, fainting, seizures, severe headache, and hot skin. The skin may be dry or sweaty, so the presence or absence of sweat does not rule it out. Fast heartbeat, nausea, vomiting, and trouble walking can also happen.
Causes and Risk Factors
Heatstroke is caused by heat building up in the body faster than it can be released. Hot and humid weather, heavy exercise, dehydration, poor airflow, and wearing heavy or tight clothing can raise the risk. Some medicines and health conditions can also make it harder for the body to manage heat.
Who Is Affected
Anyone can develop heatstroke, especially during heat waves or strenuous activity in the heat. Higher-risk groups include older adults, babies and young children, pregnant people, people with heart, lung, or kidney disease, people who work outdoors, and athletes. People without access to shade, water, or cooling are also at greater risk.
Prevention
During hot weather, drink fluids regularly, rest in shaded or cooled places, and wear lightweight clothing if possible. Limit hard physical activity during the hottest part of the day and increase activity gradually when adjusting to heat. Never leave a child, older adult, or pet in a parked vehicle, even for a short time.
Treatment Categories
Heatstroke needs emergency medical treatment. While waiting for emergency help, move the person to a cooler place and start cooling them with cool water, wet cloths, fans, or ice packs placed on the neck, armpits, and groin if available. If the person is unconscious, having a seizure, or unable to drink safely, do not give food or drinks by mouth.
When to Seek Medical Care
Seek medical care right away for symptoms of heat illness such as dizziness, vomiting, weakness, or worsening cramps, especially if symptoms do not improve quickly after moving to a cool place. Medical advice is also important for people at higher risk, even if symptoms seem mild at first. Heat illness can worsen fast.
When It May Be an Emergency
Call emergency services immediately if someone has confusion, faints, has a seizure, cannot drink, has trouble breathing, or seems severely ill after heat exposure or exercise in the heat. These are signs of possible heatstroke. Start cooling the person while waiting for emergency help.