Health Library

Heat intolerance

Sensitivity to heat; Intolerance to heat

Heat intolerance is a feeling of being overheated when the temperature around you rises. It can often cause heavy sweating.

Heat intolerance usually comes on slowly and lasts for a long time, but it may also occur quickly and be due to a serious illness.

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Causes

Heat intolerance may be caused by:

• Amphetamines or other stimulants, including those found in drugs that suppress your appetite
• Anxiety
• Caffeine
• Menopause
• Too much thyroid hormone (thyrotoxicosis)

Home Care

Exposure to extreme heat and sun can cause heat emergencies or illnesses. You can prevent heat illnesses by:

• Drinking plenty of fluids
• Keeping inside room temperatures at a comfortable level
• Limiting how much time you spend outdoors in hot, humid weather

When to Contact a Medical Professional

Contact your health care provider if you have unexplained heat intolerance.

What to Expect at Your Office Visit

Your provider will take a medical history and perform a physical examination.

Your provider may ask you questions like these:

• When do your symptoms occur?
• Have you had heat intolerance before?
• Is it worse when you exercise?
• Do you have vision changes?
• Are you dizzy or fainting?
• Do you have sweating or flushing?
• Do you have numbness or weakness?
• Is your heart beating fast, or do you have a rapid pulse?

Tests that may be performed include:

• Blood studies
• Thyroid studies (TSH, T3, free T4)

References

Hollenberg A, Wiersinga WM. Hyperthyroid disorders. In: Melmed S, Auchus RJ, Goldfine AB, Koenig RJ, Rosen CJ, eds. Williams Textbook of Endocrinology. 14th ed. Philadelphia, PA: Elsevier; 2020:chap 12.

Jonklaas J, Cooper DS. Thyroid. In: Goldman L, Schafer AI, eds. Goldman-Cecil Medicine. 26th ed. Philadelphia, PA: Elsevier; 2020:chap 213.

Sawka MN, O'Connor FG. Disorders due to heat and cold. In: Goldman L, Schafer AI, eds. Goldman-Cecil Medicine. 26th ed. Philadelphia, PA: Elsevier; 2020:chap 101.

Review Date: 1/18/2022  

Reviewed By: David C. Dugdale, III, MD, Professor of Medicine, Division of General Medicine, Department of Medicine, University of Washington School of Medicine. Also reviewed by David Zieve, MD, MHA, Medical Director, Brenda Conaway, Editorial Director, and the A.D.A.M. Editorial team.

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