Originally published on 27th June 2017 Last updated on 16th February 2024
As well as cold intolerance, which is where you feel particularly reactive to cold temperatures, heat intolerance can be a symptom of thyroid disease, too. This symptom can also be made worse by rising temperatures outside.
If you feel easily hot, especially compared to others around you, have hot flushes and do not cope well in hot weather, this may suggest that you experience heat intolerance.
This can be linked to hypothyroidism for a few reasons.
1. Over Medication for Hypothyroidism
I would firstly check that you’re not over medicated on your thyroid medication, as being so can lead to hyperthyroidism and thus cause symptoms such as feeling hot, flushed and anxious (see here for hyperthyroidism heat intolerance).
You need a full thyroid panel (note: full, not just one or two tests) running, to include TSH, Free T3 and Free T4, and thyroid antibodies TPOab and TGab wherever possible.
A suppressed TSH can be normal on thyroid medication containing T3 (this is debated however, so your doctor should work to find what they feel is normal and right for you), but your Free T3 and Free T4 should be within range. Please see optimal thyroid hormone levels explained here. 
TSH alone is not accurate to go by.
2. Autoimmune Hypothyroidism (Hashimoto’s)
Should you be having a Hashimoto’s flare from this swinging, it can cause increased intolerance to temperatures.
To check for Hashimoto’s and to monitor how you are doing (e.g. if it’s calming down), you need those two antibodies tests TPOab and TGab running. You can read how to better manage it here. Find out how to order your own testing here.
3. Sex Hormones
Also a part of the same system (the endocrine system) are your sex hormones, which may work in tandem with your thyroid hormones.
When one goes wonky, so can others.
Sex hormone imbalances coming hand in hand with thyroid problems seem to be increasingly common, so testing your progesterone and oestrogen levels may be helpful. If a doctor won’t do this for you, you can arrange it yourself.
If you’re of a particular age, considering the menopause or perimenopause would also be a good idea for your heat intolerance symptoms. Many people are diagnosed with hypothyroidism around the common age for menopause and perimenopause to start.
4. Adrenal Dysfunction
The adrenal glands are also part of the endocrine system and many thyroid patients find that they develop adrenal dysfunction on top of thyroid disease.
Adrenal dysfunction (note: it may also be referred to as hypothalamic-pituitary axis dysfunction) seems pretty common among thyroid patients and testing for it with a 24 hour, four point saliva test can show if you do indeed have it.
When I had high cortisol adrenal fatigue, it was causing me to have hot flushes where I became unbearably hot and sweat buckets. Even in December!
What you need to keep in mind about your thyroid, is that it’s basically your body’s thermostat, regulating body temperature. But when you have a thyroid problem or heat intolerance, it won’t adjust or adapt to colder or warmer external temperatures like a regular person’s, which means you can struggle in the heat. Or the cold.
As well as taking into consideration the above info and exploring them, some of these tips may also help you to cope with feeling overwhelmingly hot.
- Look at investing in a cooling pillow pad.
- Take a cool shower before bed to cool down and remove sweat and stickiness.
- Replace a heavy duvet with a light sheet.
- Stay in a cool room.
- Spray your bed sheets in cold water so that as you lay on them, they’ll slowly dry but help keep you cool in the process.
- Drink cold drinks, preferably water, with ice.
- You can also suck on ice cubes to help you cool down and hydrate at the same time.
- Enjoy ice lollies and ice cream!
- Applying bags of ice cubes, ice packs or frozen peas to your wrists, back of neck and feet can also help cool you down.
- Consider investing in a fan or air conditioning at home, especially in the warmer rooms of the house and your bedroom so that your sleep is affected as little as possible. You can also try placing bottles of frozen water behind or in front of fans for a cooler breeze.
- Keep curtains and blinds closed during the day to keep heat out.
- Use cotton bed linen and clothing as it is breathable and allows ventilation.
- You can also stick your bed sheets in the fridge or freezer (in a bag) for 5 minutes or so before bed, to cool them down, too.
- Wear lighter colours such as white that reflect sunlight and avoid black and dark colours which can ‘absorb’ some heat and make you feel warmer.
- Wear loose fitting clothes for ventilation.
- Snack on frozen fruit.
- Run your wrists under cool water.
What other tips would you add? Let me know in the comments below.
You can click on the hyperlinks in the above post to learn more and see references to information given.