Heat intolerance: what it is, common causes, and more

Medically reviewed by Neka Miller, PhD on December 16, 2019. Written by Jordana White. To give you technically accurate, evidence-based information, content published on the Everlywell blog is reviewed by credentialed professionals with expertise in medical and bioscience fields.

You may have heat intolerance (also called heat sensitivity) if you often find yourself feeling too hot in indoor or outdoor temperatures that other people perceive as pleasant or comfortable. If that’s something you experience, you may be wondering: what can cause heat intolerance? That’s what you’ll discover here—plus related health conditions, remedies, and more—so read on.

What is heat intolerance?

For the human body to maintain a stable temperature, there needs to be a balance of heat production and heat loss. However, certain health and lifestyle conditions can upset this balance. When this happens, you may experience heat intolerance—meaning you’ll frequently feel uncomfortably hot in otherwise normal temperatures that don’t cause other people to feel too hot.

Common causes of heat intolerance

What can cause heat intolerance? Several different factors can make it more difficult for your body to regulate its temperature, including:

Hyperthyroidism

Hyperthyroidism (overactive thyroid) is a thyroid condition involving elevated production of thyroid hormones, which circulate in the bloodstream and are responsible for regulating many key processes in the body. Too much thyroid hormone can put your metabolism into overdrive, potentially causing excessive sweating and heat intolerance.

Easily check 3 main thyroid hormones, plus thyroid antibodies, from the convenience of home with our at-home Thyroid Test.

Perimenopause

During the menopausal transition—the years leading up to menopause—estrogen levels fluctuate before eventually dropping permanently. Research suggests that this drop in estrogen impacts the part of the brain responsible for regulating body temperature, which may be why many women in this stage of life experience “hot flashes”—sudden, brief sensations of intense warmth that often includes flushing, sweating, and chills.

Check your hormones for indicators that you’re transitioning towards menopause from the comfort of home with the Everlywell at-home Perimenopause Test.

Medications

Studies show that some medications can change your body's response to heat, causing you to become more sensitive to temperature fluctuations. Blood pressure and allergy medications, as well as many decongestants, are common culprits.

Blood pressure medications can limit the amount of blood that flows to your skin, which can limit your ability to sweat—making it harder for the body to cool down. Some allergy medications can also keep you from sweating. Decongestants limit your blood flow and increase your body’s muscular activity, which can raise your body temperature.

Certain antidepressants can also impact your sweat glands and increase your sensitivity to heat.

Caffeine intake

Caffeine in coffee, soda, and tea acts as a stimulant, meaning it can speed up your heart rate and your metabolism. Together, these factors can raise your body temperature, making you feel uncomfortably warm.

Health conditions related to heat intolerance

Certain diseases or chronic conditions can make you more likely to experience heat sensitivity. These include:

Multiple sclerosis (MS)

According to research, this autoimmune disease affects your central nervous system, which is made up of your brain and spinal cord. Specifically, MS damages the protective covering (myelin) of the central nervous system. When myelin is damaged, the nerve signals in your body get interrupted, which can ultimately lead to heat intolerance.

Diabetes

If you have type 1 or 2 diabetes that’s caused damage to your nerves or blood vessels, your sweat glands may also be affected. Studies show that this could make it more difficult for your body to cool off in the heat.

Seeking medical care for heat intolerance

If you suspect you have heat intolerance, discuss your symptoms with a healthcare provider. They may recommend treating your heat intolerance by managing underlying medical conditions, like hyperthyroidism.

Remedies for heat intolerance

Here are a few tips you can use to help manage heat intolerance:

• Remain indoors when it’s hot outside and use fans or air conditioning if they’re available.
• If you are heat intolerant, you may dehydrate easily due to excessive sweating—so be sure to drink adequate amounts of water to avoid this.
• Opt for lightweight, breathable fabrics that let air reach your skin to help it cool off.

Certain thyroid conditions, as well as the menopause transition, can affect how your body feels in otherwise normal temperatures. To check your thyroid hormones from the convenience of home, take the at-home Thyroid Test. Check hormones related to the menopausal transition with the at-home Perimenopause Test.

References

1. Kingma BR, Frijns AJ, Schellen L, van Marken Lichtenbelt WD. Beyond the classic thermoneutral zone: Including thermal comfort. Temperature (Austin). 2014;1(2):142-149. Published 2014 Jul 8. doi:10.4161/temp.29702

2. Freedman RR. Menopausal hot flashes: mechanisms, endocrinology, treatment. J Steroid Biochem Mol Biol. 2014;142:115-120. doi:10.1016/j.jsbmb.2013.08.010

3. Epstein Y, Albukrek D, Kalmovitc B, Moran DS, Shapiro Y. Heat intolerance induced by antidepressants. Ann N Y Acad Sci. 1997;813:553-558. doi:10.1111/j.1749-6632.1997.tb51746.x

4. Flensner G, Ek AC, Söderhamn O, Landtblom AM. Sensitivity to heat in MS patients: a factor strongly influencing symptomology--an explorative survey. BMC Neurol. 2011;11:27. Published 2011 Feb 25. doi:10.1186/1471-2377-11-27

5. Kenny GP, Sigal RJ, McGinn R. Body temperature regulation in diabetes. Temperature (Austin). 2016;3(1):119-145. Published 2016 Jan 4. doi:10.1080/23328940.2015.1131506