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 a serious illness.
Sensitivity to heat; Intolerance to heat
Heat intolerance may be caused by:
- Amphetamines or other stimulants, such as those found in drugs that suppress your appetite
- Too much thyroid hormone (thyrotoxicosis)
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
Call 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:
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.