Thyroid & Cold Intolerance…Heat Intolerance Too!

Thyroid & Cold Intolerance...Heat Intolerance Too!

I’m cold. All. The. Time.

I need to wear a sweater in summer to keep from freezing.

My body just can’t handle the air conditioning in my workplace.

But what about me? I’m hot all the time.

Here I am wearing a sleeveless shirt in the dead of winter.

Sleep without my fan? Impossible.

Written by Kent Holtorf, MD

Thermoregulation and Cold Intolerance

As the temperature drops, the thyroid must work harder to maintain various aspects of bodily function including thermoregulation and metabolism. A primary role of the thyroid is thermoregulation, which helps keep the body at a healthy temperature of 98.6 degrees Fahrenheit or 37 degrees Celsius.

Those with thyroid conditions tend to be less capable of dealing with cold weather. Inability to maintain proper body heat can lead to cold intolerance.

In fact, some of the most common causal factors of cold intolerance involve hormone function. There are three major contributors that are commonly found in those who are cold intolerant.

♦ Hypothyroidism, reduced thyroid activity, leads to a reduced metabolic rate. As metabolism reduces, the body becomes decreasingly effective at producing heat.

♦ Hyperthyroidism, overactive thyroid activity, can cause individuals to have less fat and reduced muscle mass. Both fat and muscle act as a sort of insulation and help regulate body heat.

♦ A dysfunctional hypothalamus, the gland located in the brain that regulates core body temperature, can cause significant fluctuations in body temperature. If this system malfunctions, body temperatures can be allocated to improper ranges.

Cold Weather and The Thyroid

Cold weather has a notable impact on those with thyroid conditions, but it can also impact the thyroid of healthy individuals. Because the body requires more heat, it produces additional TSH in order to boost metabolic action. Due to this influx of TSH (this commonly occurs during extended periods of cold weather), one may be incorrectly diagnosed with mild hypothyroidism, or subclinical hypothyroidism. To avoid misdiagnosis, it is best to have multiple tests done in different seasons as hormone levels fluctuate dependent on moderate and cold seasons.

In a 2013 study, published in the Journal of Clinical Endocrinology & Metabolism, a shift was recognized in thyroid stimulating hormone (TSH) levels based on the season. Tests gauging TSH levels were conducted monthly among 1,751 individuals diagnosed with subclinical hypothyroidism and 28,096 healthy individuals with normal thyroid function. Results showed that there is a definite seasonal pattern in TSH levels. In both groups, levels of TSH decreased during the summer and fall months and increased during the winter months all the way through to the spring. This data, as suggested by David S. Cooper, MD, could be the body compensating for cold weather by increasing hormone production and thereby boosting metabolic function. As this study shows, a thyroid condition is not required to feel the impact of system-slowing effects brought on by cold weather.

Those with thyroid conditions have reduced tolerance to cold and are at greater risk of hypothermia. Additionally, research shows that living in a colder climate is also a risk factor for developing thyroid cancer. Researchers looked at correlations between average temperature by state, and the rates of thyroid cancers. (They adjusted for exposure to radiation, a key risk factor for thyroid cancer.) What they found was that living in colder areas significantly increases the risk of developing thyroid cancer. For example, living in Alaska actually doubled the risk of thyroid cancer, compared to a warmer state such as Texas. Maybe the snowbirds who head to a warmer climate for the winter have the right idea!

The Weather and Your Thyroid Medication

If you are hypothyroid, you may notice that if you stay on a steady dose of thyroid hormone replacement medication during colder months, you may feel somewhat more hypothyroid. Some physicians routinely recommend that their hypothyroid patients raise their medication dosage slightly during colder months, and drop back down to a lower dose during warmer temperatures. If you notice hypothyroidism symptoms becoming more troublesome during colder weather, you may want to ask your doctor about a seasonal dosage adjustment.

What About Heat Intolerance and The Thyroid?

A frequently overlooked indicator of thyroid dysfunction is intolerance to warmer conditions.

Typically, this symptom presents itself in hyperthyroid patients. However, any form of thyroid dysfunction, especially those related to autoimmune dysfunction, can result in a person suffering from poor temperature regulation.

Recognizing the lesser known symptom of heat intolerance and its relation to thyroid function is an important step in identifying and treating thyroid dysfunction.

When functioning correctly, the thyroid actively responds to changes in temperature by appropriately adjusting basal metabolic rate (BMR) and releasing hormones to promote cellular release or retention of heat. This action keeps the body at a comfortable and functional temperature. However, when the thyroid is not at its best, the body loses much of its capacity to regulate temperature.

Intolerance to cold or an inability to stay warm is a common indicator of hypothyroidism. Hyperthyroidism causes overactive cell function resulting in multiple symptoms including sensitivity to heat. While this is the most common presentation of symptoms, the opposite is possible as well and can make symptoms confusing to interpret.

Autoimmunity and Hashimoto’s

A number of hypothyroid patients suffer from some degree of autoimmune dysfunction resulting in multiple issues including heat intolerance.

Hashimoto’s thyroiditis is a common autoimmune disorder. Hashimoto’s causes the body’s defenses to attack its own thyroid tissue. Symptoms of Hashimoto’s manifest differently depending on the patient. There are multiple symptoms associated with Hashimoto’s but the intensity and frequency of such symptoms can be drastically varied. Generally, symptoms begin mild and then continue to intensify over time if inflammation and the malfunctioning immune response is not resolved.

Common symptoms of Hashimoto’s include:

♦ Fatigue
♦ Weight gain
♦ Altered mood, particularly malaise and depression
♦ Difficulty maintaining focus
♦ Dry skin or lips, rashes, and brittle hair
♦ Constipation
♦ Fluid retention leading to bloating in the face and lower extremities
♦ Hoarseness or difficulty speaking
♦ Inability to sweat or reduced perspiration
♦ Heat sensitivity
♦ Changes in menstruation
♦ Joint and muscle pain

Hashimoto’s Hormone Spikes and Hot Flashes

Patients with Hashimoto’s experience a range of symptoms alternating between hypothyroidism and hyperthyroidism. This is caused by damage being done directly to the thyroid that limits hormone production resulting in a net loss of thyroid hormone. However, as portions of the thyroid are destroyed there is a temporary release of thyroid hormone that can temporarily elevate hormone levels. A spike in thyroid hormone such as this can result in symptoms related to hyperthyroidism including extreme susceptibility to heat and hot flashes. This can occur even though the patient’s thyroid production indicates hypothyroidism.

Temporary hormone spikes can result in episodes of fatigue, hot flashes, anxiety, jitteriness, and weight fluctuations. Furthermore, patients can suddenly become incapable of cooling down when they were previously unable to stay warm. This can be highly jarring for those with hypothyroidism.

Overmedicated hypothyroid patients experience issues similar to Hashimoto’s-related hormone spikes. Over supplementation of thyroid hormones may push a hypothyroid patient into hyperthyroid states resulting in many different symptoms including heat intolerance.

Triggered Symptom Flares

Hashimoto’s symptoms can alter over time and periodically flare up or temporarily worsen due to different triggers. Flares generally exacerbate current symptoms.

If a patient is experiencing Hashimoto’s related symptoms such as sensitivity to heat, a flare up can abruptly worsen their already reduced ability to regulate body temperature. Usually, autoimmune flare ups have an external trigger.

Those with autoimmune disorders have a highly sensitive and reactive immune system. This means that even minor changes in diet, activity level, stress, allergen exposure and others can trigger an immune response resulting in increased symptom intensity.

A Hashimoto’s-related flare up may be identified through the following symptoms:

♦ Abrupt worsening of fatigue
♦ Unexplained weight gain
♦ Malaise or depression
♦ Sudden worsening of joint pain, muscle pain, and weakness
♦ Anxiety, jitteriness, and racing heart
♦ Abrupt onset of brain fog and difficulty concentrating 
♦ Digestive issues or changes in gastrointestinal function
♦ Hot flashes or difficulty regulating body temperature

Regardless of the symptoms that manifest, it’s most important to identify what initiated the response. Recognizing the trigger allows patients to avoid and minimize future autoimmune and inflammatory responses, which helps reduce symptom occurrence and intensity.

Common autoimmune triggers include:

♦ Physiological or emotional stress
♦ Physical trauma including sport related injury, car accident, etc.
♦ Chronic nutrient deficiencies
♦ Viral, bacterial, or fungal infections
♦ Hormone imbalances
♦ Food allergies or sensitivities
♦ Stress
♦ Lack of sleep

Remember to listen to your body and respond appropriately. If you feel cold or hot quicker than others and just can’t seem to warm up or cool down no matter what you do, get checked for thyroid dysfunction. An abnormal reaction to heat or cold may serve as a sign of thyroid dysfunction that is undiagnosed or not well treated.

About Dr. Kent Holtorf

Kent Holtorf, M.D. is the medical director of the Holtorf Medical Group with locations in Los Angeles, Foster City, Atlanta, and Philadelphia. He is also founder and director of the non-profit National Academy of Hypothyroidism (NAH), which is dedicated to dissemination of new information to doctors and patients on the diagnosis and treatment of hypothyroidism.

Dr. Holtorf has personally trained numerous physicians across the country in the use of bioidentical hormones, hypothyroidism, complex endocrine dysfunction, and innovative treatments of chronic fatigue syndrome, weight loss, fibromyalgia, and chronic infectious diseases, including Lyme disease. He has been a featured guest on numerous TV shows including CNBC, ABC News, CNN, EXTRA TV, Discovery Health, The Learning Channel, The Today Show, The Doctors, Dr. Dean Edell, Glenn Beck, Nancy Grace, Fox Business, ESPN, Rush Limbaugh, CBS Sunday Morning, Sean Hannity, So Cal News, and quoted in numerous print media including the Wall Street Journal, Los Angeles Times, US New and World Report, San Francisco Chronicle, WebMD, Health, Elle, Better Homes and Garden, US Weekly, Forbes, Cosmopolitan, New York Daily News, Self magazine, among many others.

READ NEXT: When Hypothyroidism is Painful: Musculoskeletal Manifestations

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About Dana Trentini

Dana Trentini founded Hypothyroid Mom October 2012 in memory of the unborn baby she lost to hypothyroidism. This is for informational purposes only and should not be considered a substitute for consulting your physician regarding medical advice pertaining to your health. Hypothyroid Mom includes affiliate links including the Amazon Services LLC Associates Program.


  1. Rhonda Shields says

    7 years ago my dr removed all my thyroid but a tiny piece now I am on 300mcg of levothroxine the last 2 times i had bloodwork the Dr says it looks like I’m not taking meds has anyone had this to happen would love to hear from you.

    • Tammy French says

      I just started taking levothroxine June 1 2020. Most of my six siblings have thyroid issues.. I was doomed I guess. I have always been a small person but started gaining weight.. I’m hoping this is the problem like the others

    • Tanya Albertson says

      That’s a very high dose. I was on it and switched to synthroid. That worked better. There are a lot of fillers in levothyroxine. Sometimes they inhibit the body of absorbing the medicine correctly. See if your doc will switch you to Synthroid.

    • Catherine Reid says

      When and how you take your medication is very important. Levothyroxine should be taken on an empty stomach with no food or any other medication, an hour on either side of taking it. Also do not take it with coffee. Do you take ant selenium? It sounds like you may have absorption issues. I have no thyroid and was on 200 to 300mcg of levothyroxine but still felt awful! But once I learned about how and when is best to take levothyroxine, my absorption was better and I actually reduced my meds to almost half and feel so much better. Selenium also helps with conversion . Lots around about these issues on internet but doctors fail to tell you this! I have no thyroid at all for 50 years.

  2. I have an underactive thyroid, ulcerative colitis and menapausal, I’m on the lowest dosage of thyroxine as any higher sends my heart rate through the roof. My skin pinks up when I am burning hot which is 90% of the time, the rest of the time I’m freezing cold, I eat healthy but have gained approx half a stone a year for last 12 yes, only time i lose weight is if I have a major colitis flare up and end up in hospital and can lose 2-3 stones in couple of weeks, then gain it back with endless steroids for next few months. I get major joint pains and take vitamins etc to help, I now also have gall stones and plantaris in my feet so also had injections to help with that. I wish there was something to help me.

    • ANITA BHATIA says


      • I’m the same.i can’t get help doctors will not put levothyrixine up.i have heat problems and menopausal it pur a lot of strane on my marriages. Please some one help my life is ruled by my body.

    • I thought you were talking about me! I’m there, and it’s not getting better. Levothyroxine is not working for me…112mg at the moment!
      Be well and be safe,

  3. Isabel sevilla says

    I’ve had hypothyroidism for like about over 10 years ..and it affects me more in the heat then in cold weather ..I cant sleep at night my arms start to hurt and they get really really cold ..I’ve also started getting aches in my legs as well the colder weather I’m fine ..its so frustrating

  4. Anyone with Reffetofs syndrome out there?

  5. Hi. I am 62 years old and been taking cortef and synthroid for the last 27 years. After natural childbirth I was diagnosed with Sheehan’s Syndrome. My endocrinologist retired a few years back and I have not been feeling up to my normal levels for at least 3 years now. Can you tell us anything about Shehan’s syndrome? And possibly recommend a very good Dr. I’m the 48602 area code?

  6. Diane Landenglos says

    I just had a TPO blood test. Results were negative (which surprised my Endocrinologist & me). My TPO was 15, I have a pretty thick family history of Hashimoto’s, as well as malignant thyroid/nodules and recently discovered, through a Thyroid specific ultrasound, that I have a goiter w/a nodule. I have many symptoms, as well. Why are we (me & doctors), doing the wait & see treatment plan. So frustrating.

    • Hi Diane, It is a very frustrating situation when Hashimoto’s can show up with normal antibody levels. I recommend that you have your antibodies, both Thyroid Peroxidase Antibodies and Thyroglobulin Antibodies, tested several times over the course of time. It can take multiple tests to catch elevated antibodies. Even then it is possible to show up normal on lab tests. I wonder if the ultrasound indicated whether the texture was homogeneous or heterogenous. Heterogenous is the typical texture appearance with Hashimoto’s. I too am in a similar situation with normal antibody tests multiple times. A biopsy can give conclusive results for Hashimoto’s but I have not done that since I have no other reason to do it. If you are told to have your goiter and nodule biopsied at some point if it becomes necessary be sure to ask for them to determine whether or not you have Hashimoto’s from the results. Given your family history I would assume you have hypothyroidism and do all the things that I mention at Hypothyroid Mom to balance the immune system. That is what I do and I actually feel most things related to autoimmunity are things everyone with hypothyroidism should look into.

    • Diana Buckmaster says

      When I was married in 1988 I weighed 85 lbs. After my 1st child in 1989 I was diagnosed with Hashimoto’s Hypothyroidism in 1990. Was on various meds for many years then after my 2nd child in 1995 I had a huge goiter . In 1998 I has Radioactive Iodine Treatment done. In 2000 had thyroid removed. In 2001 was diagnosed with type 2 diabetes. I weighed 185. I am 5 foot tall. My meds changed frequently. I walk about 5 miles a day, eat healthy. No sugar. Only unsweetened tea and water to drink still 180 lbs. Beyond frustrating.

  7. Carla Ricketts says

    Hi, is there a blood test for Hashimoto’s as I’m on medication for underactive thyroid alreadly. my symptoms match hastimotos.

    • Hi Carla, There are two thyroid antibodies to test for Hashimoto’s: Thyroid Peroxidase Antibodies & Thyroglobulin Antibodies. All the best from Hypothyroid Mom.

  8. sounds to me like a digestive problem. I just found out that is what is wrong with me. My system is ass backwards. used to be if i ate processed food i was fine and could go to the bathroom (2). then it started making me gain weight and i am usually skinny. then i started gaining weight for no reason and tried getting rid of processed food and eating whole foods (root). now my system wont even digest that and i look like i am 4 months prego. wtf. i go pee alot but no no 2. w t f is wrong with me. guess its time for a colonoscopy. unreal. i am on thyroid medication but cant really take it because it makes me wired and tired at the same time and makes my pupils look real small like i am f… high. and i am on the lowest dose of armour. help!

  9. I am 58 and despite my complaints to my doctor about my healthy eating, but a steady weight gain, my being cold all the time, can’t concentrate…on and on…he said your TSH is “normal”. Eventually I landed a hormone doctor, for my estrogen and progesterone, and she said, hey, you have a hypothyroid. I’ve tried Synthroid, it was what my regular doctor was willing to prescribe, that made my heart problem worse, then Armour, same thing, and now Nature Throid. And suddenly, I’m hot all the time! I can’t get cool enough, and I haven’t lost weight, despite my eating habits and walking regimen. My hormone doctor has increased my Nature Throid this week, hopefully I’ll find relief. But the being hot all the time, it’s not menopausal, it’s not hot flashes, it’s hot 24/7. When I looked up all the thyroid medications, every single one of them listed “heat intolerance” as a side effect. So I’m beginning to think it’s the medication and not my condition that’s causing the heat intolerance.

    • Have you tried the elimination diet? Even “healthy food” can be a trigger…

    • Robyn Reed says

      Hi Sherry, I found your post very interesting. I have been on Thyroid medication for about 5 years now and I have become intolerant of heat. I too, am hot 24/7. The other day I was outdoors and it was windy and cold, everyone was wrapped up and complaining of the cold. I was in a T shirt and was hot. You may have solved the problem, it may be the medication. Good luck resolving the problem.

    • I have the same problem withy body wayyy overheating and I can’t cool down quick enough,I had a complete Thyroidectomy 7-8 years ago,Was put on synthroid 125 mcg,had labs 2 months ago, synthroid was bumped up to 150,This overheating started a year ago and this summer it’s really really bad and getting worse!! I have severe nauseas/vomiting and sour stomach and bad constipation,then diarrhea.. I had rectal bleeding 3 weeks ago,I’ve had 2 colonoscopy and 2 EGD,Dr wants to do another colonoscopy,he removed 2 abnormal polyps,took biopsies,I’m waiting on a follow-up..I was told in January I have Gastropraris,I can’t get my BP regulated,it runs 180-200/100-110 ,my BP meds was increased in mg,still didn’t help,I also have severe joint pain, especially my hips and can barely walk most days, early mornings,my right leg stays numb, tingling….I feel like I need a Neaurologist

    • Finally! I’ve been trying to find away to describe the waves of heat the plague me daily. NOT hot flashes! I know the difference. Started a few months back, it felt like my body was trying to sweat, but couldn’t. Hot for 30 seconds then cool down, repeat, sometime all day long. If I sit still this awful symptom seems to not be as intense. However, if I try to do any activity, from cleaning house to yard work, the heat waves are debilitating.
      I am very scared at this point that I can’t get a doctor to listen, they just base their decision to not treat on numbers: (which apparently are normal)
      Free T4 0.6
      Free T3 3.0
      TSH 1.9
      I’ve had only one doctor say he thinks I alternate between hyper/hypo, but any advice other than avoid dairy, gluten, soy ( he has the same advice for every patient he sees).
      In last 12 months I’ve had :
      30 pound weight gain (9 months time, no eating changes)
      Severe insomnia
      Anxiety( new to me)
      Severe cracked heels
      Heat/cold intolerance ( heat waves)
      Dry eye, hair
      Pain throughout body, tendinitis requiring injections
      Diarrhea/ constipation
      Low grade fevers
      Gallbladder issues
      Lack of motivation
      Low libido
      Numbness in foot
      Carpal tunnel…. and so much more

      Will I become another statistic, being told it’s all in my head, there is nothing wrong. My health has steadily declined for many years with a family history of thyroid issues. I have children at home still, one with disabilities, several with autoimmune type symptoms. I want to be able to help them not become as ill as I have. I’m not sure howmuch more this body can take as far as putting on the smiley face everyday. I get up and do the best I can everyday, but would love to sleep a day away here and there, right?! Lol!!!
      I just don’t want my kids to remember mom as never feeling well and darn it I want to enjoy my life:). Any input is appreciated and I’m sorry for the long post, just couldn’t believe someone was describing these heat issues.
      Kindly, Rachel

      • Hi Rachel, I can identify with at least 10 of the issues on your list and can sympathise with you. I understand your anxiety that your children are going to think of you as someone who does not feel well a lot of the time because I too worry my family think the same. As the symptoms are numerous and appear randomly and may be some or one or two at a time I tend to not mention them as Worry as to adult children’s views of me.
        I am hypothyroid and am a male so this can affect both sexes. My Doctor says My medication is sufficient but after reading posts on a couple of forums are going to go back armed with more facts.
        I hope you manage to alleviate some of your symptoms and your family can come to accept your illness for what it is a terrible blight but not what defines you as a mother.

  10. Adriane Valdivia says

    I have been trying to get pregnant and I decided to go to an endocrinologist. She diagnosed me with hashimoto’s desease.
    Now I move and I am in Clayton NC waiting to be seen for a new doctor. So far synthroid and metformin has been pre-scribe.
    Do you know any doctors in the Raleigh area? Can you refer me to more info?

    • alternative to Metformin is NanoGluco from Biopharma Scientific. Let them know Lisa Miller is the referring health coach.

  11. Ruby Butler says

    I need help in locating a endocrinologist for my daughter. She had her thyroid removed in college. And has struggled since with finding a doctor that does more than look at labs but also listens to how she is feeling. She is having problems getting the Nature thyroid medication that is the only thing that she has felt close to normal on in 20 years. She also struggles from a poor adrenal function. We live on the Lexington KY area. Have had no luck finding a good doctor. Any list or recommendations? The ones she likes are not taking new patients. HELP

  12. Im 66 years young! have been on thyroid replacement for years until 2013. im on no pharma scripts now, except for antibiotic for sinus infection. diagnosed with hypothyroisism, low coritisol, several thyroid nodules and one is calcified. I live in Fairbanks Alaska (7 months in dark in winter). I do take Bio D Emulsion drops. Can you tell me what causes thyroid calcification? No nuclear exposure. I was on Iosol II TCPS drops 15 daily of a friend, my thyroid nodules grew larger, and Endo Dr. told me to stop TCPS Iosol II drops completely. Can you offer some assistance? Truly, Bella

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