Heat Exhaustion
Informed by recognized medical guidance
If symptoms are severe, worsening, or life-threatening, seek urgent medical care now.
Overview
Heat exhaustion is a condition where your body gets too hot and cannot cool itself down properly. It often happens when you are active in high temperatures or humidity. If not treated quickly, it can lead to heatstroke, which is more serious.
Key facts
- Heat exhaustion is a heat-related illness that can progress to heatstroke if not treated.
- It is caused by losing too much water and salt through sweating.
- Symptoms include heavy sweating, weakness, dizziness, and nausea.
Yes, heat exhaustion is common, especially during heat waves, in hot climates, or when doing strenuous activity in warm weather.
Anyone can get heat exhaustion, but it is more likely in older adults, young children, people with certain chronic health conditions, and those who work or exercise outdoors.
Symptoms
- Hot, red, dry skin (not sweating)
- Confusion or unconsciousness
- Seizures
- Temperature above 40°C (104°F)
- Rapid, strong pulse or very slow pulse
- ⚠Symptoms that do not get better within 30 minutes of resting in a cool place and drinking fluids
- ⚠Vomiting that prevents you from keeping fluids down
- ⚠Severe headache or dizziness that does not go away
Common symptoms
- Heavy sweating
- Weakness or tiredness
- Dizziness or fainting
- Nausea or vomiting
- Headache
- Cool, pale, and clammy skin
- Fast but weak pulse
- Muscle cramps
Symptoms in children
- Irritability or fussiness
- Unusual tiredness
- Heat rash
- Not wanting to play or eat
Symptoms in older adults
- Confusion or disorientation
- Weakness that gets worse quickly
- Dry mouth or no tears when crying
- Dark urine
Causes
Main causes
- High outdoor temperatures, especially with high humidity
- Strenuous physical activity in hot weather
- Not drinking enough fluids when active in heat
- Wearing heavy or tight clothing in hot conditions
Risk factors
- Being very young or very old
- Having chronic illnesses like heart disease, diabetes, or obesity
- Taking certain medicines (ask your doctor if yours increase heat risk)
- Drinking alcohol or caffeine before or during heat exposure
- Being dehydrated before starting activity
When to see a doctor
See a doctor urgently if:
- If you or someone else has symptoms of heatstroke (call emergency)
- If symptoms last more than an hour despite cooling down
- If you cannot stop vomiting
Book a routine appointment if:
- If you have had heat exhaustion before and want advice on preventing it
- If you have a health condition that may make heat more dangerous
Diagnosis
A doctor will ask about your symptoms and recent activities, and check your body temperature. They may also do a physical exam to look for signs of dehydration.
Tests that may be done
- Body temperature measurement
- Blood tests to check electrolyte levels (salt and minerals)
- Urine test to see if you are dehydrated
What to expect at your appointment
The doctor will usually know if it is heat exhaustion based on your history and exam. Tests help rule out other problems and check how severe it is.
Treatment
The main treatment is to cool your body down and replace lost fluids. Most cases can be managed at home, but severe cases may need medical help.
Self-care at home
- Move to a cool, shaded, or air-conditioned place
- Lie down and raise your feet slightly
- Drink cool water or a sports drink (if you have one) in small sips
- Apply cool, wet cloths to your skin or take a cool bath
- Remove tight or unnecessary clothing
- Fan yourself or sit near a fan
Medical treatments
If self-care does not work or you are very dehydrated, a doctor may give fluids through a vein (IV) to rehydrate you quickly. They may also use cooling blankets or misting fans. No specific medications are recommended for heat exhaustion.
When is surgery considered?
Not applicable
Living with this condition
After you recover from heat exhaustion, it is important to take it easy for a day or two. Your body needs time to get back to normal. Avoid heat and heavy activity until you feel completely well.
Lifestyle tips
- Drink plenty of water during hot weather, even if you are not thirsty
- Wear lightweight, light-colored, and loose-fitting clothing
- Avoid being outside during the hottest part of the day (11 a.m. to 3 p.m.)
- Take breaks in the shade if you are working or exercising in heat
Diet and exercise
Eat light, cool meals like salads and fruits that have high water content. Avoid heavy, hot meals. Exercise in the early morning or late evening when it is cooler. Listen to your body – if you feel dizzy or tired, stop and cool down.
Mental health and emotional wellbeing
Dealing with heat exhaustion can be stressful. You may worry about it happening again. It is normal to feel anxious, but knowing how to prevent it can help you feel more in control.
Prevention
Yes, heat exhaustion can almost always be prevented by staying cool and hydrated. Plan your activities around the weather, drink fluids regularly, and take breaks in the shade or air conditioning.
Vaccines
There is no vaccine for heat exhaustion.
Screening programmes
No routine screening is needed, but if you have a health condition that increases your risk, talk to your doctor about a personal heat safety plan.
Complications
If left untreated
- Heatstroke – a life-threatening condition where the body stops sweating and temperature rises dangerously high
- Organ damage, such as to the kidneys, heart, or brain
- Dehydration that may require hospital treatment
Long-term outlook
With prompt treatment – cooling down and rehydrating – almost everyone recovers fully from heat exhaustion within a few hours to a day. It is very important to act quickly to prevent it from becoming heatstroke.
Find support
International organisations
- World Health Organization (WHO) – Heat and Health ↗
- International Federation of Red Cross and Red Crescent Societies ↗
Local organisations
- Health Canada – Extreme Heat ↗ · Canada
Helplines
External links open third-party websites. Ruqelo Health is not responsible for external content. Listing an organisation does not imply endorsement.
Always verify with your doctor
Health guidelines vary by country and region. The information in this article is based on international clinical guidelines but may not reflect the specific guidelines, medications, or practices in your country. Always discuss your health concerns with your own doctor or healthcare provider, and refer to your local national health guidelines where available.
Important notice This information is for educational purposes only. It does not replace professional medical advice, diagnosis, or treatment. Always consult a qualified healthcare provider about your specific situation. If you are experiencing a medical emergency, call your local emergency services immediately.
Related conditions
Sources and guidance
This article is educational and is prepared with reference to recognized health information and clinical guidance sources where available. Specific source links may vary by topic.
Last updated: July 16, 2026
Educational note: This information is for education only and is not a diagnosis.
Use it to support, not replace, advice from a licensed clinician.
If symptoms are severe, worsening, or urgent, call your local emergency number or seek emergency care.
Guidance may differ by country or region. Confirm local recommendations with a qualified healthcare provider.