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Heat Illness
Summary
Your body normally cools itself by sweating. During hot weather, especially when it is very humid, sweating just isn’t enough to cool you off. Your body temperature can rise to dangerous levels and you can develop a heat illness.
Most heat illnesses happen when you stay out in the heat too long. Exercising and working outside in high heat can also lead to heat illness. Older adults, young children, and those who are sick or overweight are most at risk. Taking certain medicines or drinking alcohol can also raise your risk.
Heat-related illnesses include:
- Heat stroke – a life-threatening illness in which body temperature may rise above 106 °F (41 °C) in minutes. Symptoms include dry skin, a rapid, strong pulse, dizziness, nausea, and confusion. If you see any of these signs, get medical help right away.
- Heat exhaustion – an illness that can happen after several days of exposure to high temperatures and not enough fluids. Symptoms include heavy sweating, rapid breathing, and a fast, weak pulse. If it is not treated, it can turn into heat stroke.
- Heat cramps – muscle pains or spasms that happen during heavy exercise. You usually get them in your abdomen, arms, or legs.
- Heat rash – skin irritation from excessive sweating. It is more common in young children.
You can lower your risk of heat illness by drinking fluids to prevent dehydration, replacing lost salt and minerals, and limiting your time in the heat.
Centers for Disease Control and Prevention
National Institute on Aging
Prevention and Risk Factors
- About Extreme Heat Centers for Disease Control and Prevention
- Beat the Heat: Staying Safe in the Summertime National Institutes of Health
- Extreme Heat Safety American Red Cross
Find an Expert
- American Red Cross American Red Cross
- Centers for Disease Control and Prevention Centers for Disease Control and Prevention
- National Center for Environmental Health Centers for Disease Control and Prevention
- National Institute for Occupational Safety and Health National Institute for Occupational Safety and Health
- National Institute on Aging National Institute on Aging
Clinical Trials
- ClinicalTrials.gov: Dehydration National Institutes of Health
- ClinicalTrials.gov: Heat Stress Disorders National Institutes of Health
Start Here
- Extreme Heat Department of Homeland Security
- Frequently Asked Questions (FAQ) about Extreme Heat Centers for Disease Control and Prevention
- Hot Weather Safety for Older Adults National Institute on Aging
Treatments and Therapies
- Heat Cramps, First Aid VisualDX
- Heat Exhaustion, First Aid VisualDX
- Heatstroke, First Aid VisualDX
Patient Handouts
- Heat emergencies Medical Encyclopedia
- How to avoid overheating during exercise Medical Encyclopedia
- Protecting Workers from Heat Stress Occupational Safety and Health Administration
- Protecting Yourself from Heat Stress National Institute for Occupational Safety and Health
Specifics
- Heat Exhaustion and Heat Stroke American Academy of Family Physicians
- Heat Stress National Institute for Occupational Safety and Health
- Miliaria Rubra VisualDX
Encyclopedia
- Heat intolerance Medical Encyclopedia
Older Adults
- Heat Stress in Older Adults Centers for Disease Control and Prevention
- Safety Tips for Exercising Outdoors for Older Adults National Institute on Aging
Children
- Heat Stroke and Hot Cars American College of Emergency Physicians
- Miliaria Rubra VisualDX
- Parents’ and Coaches’ Guide to Dehydration and Other Heat Illnesses in Children National Athletic Trainers’ Association
Videos and Tutorials
- Heat-Related Illnesses American College of Emergency Physicians
Related Issues
- Protect Your Heart in the Heat American Heart Association
- Safety Tips for Hot Weather Exercise Mayo Foundation for Medical Education and Research
Journal Articles
Symptoms
- Warning Signs and Symptoms of Heat-Related Illness Centers for Disease Control and Prevention