This post was originally published in November 2019, but it’s been updated with new info—plus, we thought it was appropriate to revisit this fall, when thyroid symptoms are prevalent.

Are you feeling the impact (positive or negative) of the current temperature whiplash? It’s not just you: Seasonal shifts, can have a significant impact on our overall health. But if you’re experiencing worse-than-normal symptoms, it could be a sign of thyroid dysfunction. Here are a few ways seasonal changes can impact your thyroid—and what you can do about it.

Symptoms of Thyroid Issues That Can Come With Seasonal Weather Changes

Decreased Circulation

If you’re a hypothyroidism or Hashimoto’s thyroiditis veteran, you know that an underactive thyroid can cause you to feel chilly when everyone else is comfortable. This increases during the fall and winter, when you might notice an increase in poor circulation, partially due to a slowed metabolism (heat is produced when your body burns calories—a slowed metabolism results in less calorie burning and less heat). That coldness also causes your blood vessels to constrict and allow less blood through. In practice, that looks like cold hands and feet, even if your environment is cozy.

Muscle Fatigue and Pain

Low levels of thyroid hormone in your body can not only slow down your metabolism, but they can also be tied to painful muscles. Your muscles use a lot of energy from mitochondria (the powerhouse of the cells, remember?) which are fueled from your thyroid hormone. Without enough hormone to power those little batteries it can result in higher instances of muscle pain and fatigue. You’ll notice this if you’re experiencing more pain, despite the absence of new or rigorous activities. 

Bowel Movement Changes

An underactive thyroid can also inhibit digestion, as the body tries to conserve energy and heat. This can translate to sluggish movement both in your digestive system and in your bowels. Constipation is most likely to be the result, as lower thyroid levels put the brakes on your colon and its ability to process and move waste out of your body.

Brain Fog + Memory Issues

Another standard hypothyroidism sign is trouble concentrating or brain fogginess. This can increase for lots of people during the winter, with or without a thyroid deficiency. But if you notice a steep increase in your ability to concentrate, it could be tied to your thyroid.

Anxiety + Depression

Sparse exposure to sunlight and shorter days can induce both feelings of lethargy and sluggishness. But if those symptom can be even more aggravated in those with thyroid issues (hyper or hypothyroid). Seasonal shifts impact thyroid function, which can instigate or contribute to more feelings of anxiety or depression.

Basal Body Temperature Decrease

It’s very common for your body’s thyroid-stimulating hormone (TSH) to fluctuate during seasonal shifts. Even people with overall normal thyroid function can see an increase in their TSH during colder months, as your thyroid adjusts to help regulate your body’s temperature and internal processes. But those with ongoing or chronic thyroid issues may experience more of a fluctuation of their TSH, including an overall downward trend in their basal body temperature (BBT). If you’re monitoring your body temp daily (including for family planning), you might notice that your BBT is regularly lower in colder months.

Vitamin D Deficiency

Without regular exposure to sunlight, it’s easy to quickly fall into the category of vitamin D deficiency. Those with ongoing thyroid issues are at a higher risk, because lack of vitamin D can be a root cause of thyroid dysfunction, and can cause some of the symptoms we’ve already discussed, including low energy, higher anxiety, brain fog, and muscle fatigue.

If any of these sound familiar to you and you have a diagnosed thyroid condition, it’s key to bring your symptoms to your doctor to figure out how to combat them from the inside out. Adjusting your thyroid hormone dosage, adding in supplements, or making changes to your nutritional plan can all support your thyroid and help decrease the symptoms you experience with seasonal change.

If you haven’t been diagnosed with a thyroid issue, but you’re experiencing many of these symptoms now and year-round, it’s a great time to talk to your doctor. We recommend asking for a series of thyroid blood tests that can give you a complete picture of your thyroid function, and set you on a path to feel better sooner.

Dr. Cassie Wilder

Dr. Cassie Wilder is a registered Naturopathic Medical Doctor (NMD) and founder of MIMC. Her passion is empowering her patients through education, understanding, and support through their healing journey. After graduating from Iowa State University with a Bachelors of Science in Kinesiology and Health, Dr. Wilder earned her Doctorate of Naturopathic Medicine from Southwest College of Naturopathic Medicine & Health Sciences, a fully accredited and nationally recognized institution in Phoenix, AZ. During her clinical training, she received extensive hands-on training with many leading experts in the field of functional medicine and developed a passion for treating hormonal imbalances, thyroid disorders, cardiovascular concerns, and adrenal fatigue.