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:
Kim M, Ladenson P. Thyroid. In: Goldman L, Schafer AI, eds. Goldman's Cecil Medicine. 25th ed. Philadelphia, PA: Elsevier Saunders; 2016:chap 226.
Sawka MN, O'Connor FG. Disorders due to heat and cold. In: Goldman L, Schafer AI, eds. Goldman's Cecil Medicine. 25th ed. Philadelphia, PA: Elsevier Saunders; 2016:chap 109.
Reviewed By: Laura J. Martin, MD, MPH, ABIM Board Certified in Internal Medicine and Hospice and Palliative Medicine, Atlanta, GA. Also reviewed by David Zieve, MD, MHA, Isla Ogilvie, PhD, and the A.D.A.M. Editorial team.