How Thyroid Health Impacts Metabolism (+Signs That You Have Hypothyroidism)

The thyroid gland is an often overlooked player in health and fitness, and receives little attention in the media for its impact on the metabolism. This is despite the gland being one the key drivers affecting metabolic rate. (1)

When considering that your metabolic rate plays an integral part in determining how much food you need, and, consequently, how much of you energy is stored as fat, used to build muscle, or utilized for vital bodily functions, this makes it an important factor in weight loss or fitness.

Below, we take a look at how the thyroid works, its impact on your metabolism, and how to know if yours is working properly.

What is the Thyroid and What Does it Do

As mentioned above, the thyroid is a gland in your body. It is responsible for secreting a number of hormones. Namely, triiodothyronine (T3), thyroxine (T4) and calcitonin. (2)

Triiodothyronine is the active form of thyroid hormone. This means that it is the one that exerts its impact on the body, as opposed to thyroxine, which first needs to be converted to T3 to be used by the body.

In either case, the active thyroid hormone works through binding to thyroid receptors in the cell to cause an increase in signaling which leads to a rise in heat and energy expenditure. This translates to an increase in the amount of energy you spend for doing daily activities, even those as simple as breathing or heating yourself up. It also plays a part in the breakdown of fat cells.

Calcitonin, on the other hand, has a drastically different action, and is involved in bone metabolism and the storage or use, of minerals in the bone.

5 Functions of the Thyroid

As indicated above, the thyroid has a number of important functions (2), including:

  1. Regulating body temperature
  2. Regulating bone density
  3. Increasing activity in the nervous system
  4. Speeding up food processing and regulating energy usage and fat storage
  5. Contributing to growth in children

These are all important reasons to make sure your thyroid gland is functioning properly and your thyroid hormone levels are within range of normal. However, for many unsuspecting individuals, this is not the case. Hypothyroidism or deficiency of thyroid hormones, disrupts your body temperature, heart rate, and metabolism.

Below are some signs that you might suffer from this condition and what you can do to help it.

5 Symptoms of Hypothyroidism

As mentioned, many people can be unaware that they are suffering from hypothyroidism, as a lot of the symptoms are general and quite vague. (3) These symptoms include:

  1. Fatigue and a drop in mood
  2. Susceptibility to the cold
  3. Muscle weakness
  4. Increased weight
  5. Puffy face

As can be seen above, it would be easy to confuse many of these symptoms as general fatigue or an allergic reaction. So, if you suspect that you have low thyroid hormone levels, you should consult your doctor and get the appropriate tests to confirm or deny whether or not your thyroid is not functioning optimally.

5 Effects of Hypothyroidism

Having low thyroid hormone levels can lead to serious long-term health issues. This is because these hormones not only have a direct impact on metabolism, but also a list of indirect effects on health, fitness, and well-being.

These can involve:

  1. Weight gain and obesity over time, which can then lead to insulin resistance and an increased risk of diabetes.
  2. An increased risk of depression and problems concentrating, which can then make it more difficult to complete complex tasks like problem-solving and decision-making.
  3. Lower bone density and an increased risk of osteoporosis and bone fractures.
  4. Lower regulation of blood sugar, which can also increase the risk of development of diabetes as well as hyperglycemia, which can cause a host of health problems.
  5. Lack of strength, which can make it more difficult to complete day-to-day tasks like heavy lifting.

What Can Be Done About It

One of the most obvious solutions for hypothyroidism is hormone supplementation, more commonly known as Hormone Replacement Therapy (HRT). (4)

As the name suggests, this is where artificial forms of the hormones are taken to bring levels in the body back to normal ranges. However, there are also a few diet and lifestyle changes that can be made to further help prevent hypothyroidism and bring thyroid hormone levels to within optimal amounts.

Firstly, taking in enough iodine in the diet is an essential part of treating this issue. This is because one of the central components from which thyroid hormones are made is iodine. This nutrient can be found in dark, leafy, green vegetables such as spinach. (5)

Secondly, taking in monounsaturated fats can help with hormone production, so increasing fat intake should be a consideration, particularly fats like omega-3s, which can be found in fatty fish like salmon or cod.

Taking in probiotic-rich foods, like yogurts and cheese, may also help, as the healthy bacteria in your gut could play a big role in hormone production. (6)

Finally, you should always look at implementing an exercise regimen, as this has been shown to stimulate the metabolism and hormone levels in the body. As such, a weight training program with some aerobic exercise should be completed regularly throughout the week alongside the above changes to your diet. (7)

Taken together with hormone replacement, these lifestyle changes should not only ensure normal levels of thyroid hormones, but also improve your health, both physical and mental, and fitness overall.


Your thyroid gland plays an important role in your health and wellness through releasing thyroid hormones. These control your metabolism and can have a major effect on growth, development, and overall health.

Hypothyroidism can be an often overlooked reason for a number of issues with your health and should always be checked for if suspected.

If you suffer from hypothyroidism, implementing Hormone Replacement Therapy (HRT), along with including more healthy fats and iodine into your diet and partaking in regular exercise can all help improve this condition and help you get healthier and fitter.

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