What Does the Thyroid Do?

The thyroid is a small, butterfly-shaped gland located at the base of your neck, just below the Adam’s apple. Weighing between 15 to 25 grams, this vital organ plays a crucial role in regulating metabolism, growth, development, and many other bodily functions.

Thyroid’s Role in Metabolism and Energy Levels

One of the thyroid’s most important jobs is controlling your metabolism – the process by which your body transforms the food and drink you consume into energy. Your thyroid gland produces two key hormones – thyroxine (T4) and triiodothyronine (T3) – that regulate the body’s metabolic rate at a cellular level.

Thyroid helps accelerate your metabolism to provide the energy your body needs. The thyroid hormones T3 and T4 increase the rate at which cells burn oxygen and calories. This influences how quickly the body uses fats, carbohydrates, and proteins.

If your thyroid makes too much hormone, it can speed up your metabolism, leading to unintended weight loss, a racing heart, sweating, anxiety, and difficulty sleeping. On the other hand, too little thyroid hormone slows metabolism down, potentially causing fatigue, weight gain, feeling cold, and other hypothyroidism symptoms.

Overall, keeping thyroid hormone levels balanced is essential for maintaining normal metabolism and a healthy weight. The thyroid directly impacts how many calories you burn at rest and during physical activity. When thyroid disorders throw off this balance, it affects your entire body.

Growth and Development

The thyroid plays a major role in physical growth and development in humans. Thyroid hormones are particularly important for brain development in babies and children.

Congenital hypothyroidism, if left untreated after birth, can lead to cretinism – a condition characterized by stunted physical and mental development. This highlights the importance of newborn thyroid screening.

Thyroid hormones also influence growth plate development in bones, which controls bone growth in kids and teens. Maintaining adequate thyroid hormone levels during childhood and adolescence helps ensure proper growth and maturation.

In adults, the thyroid gland continues to impact metabolic processes related to growth and repair. This includes the growth of hair and nails. The thyroid supports the cellular processes needed for tissue regeneration and healing.

Thyroid Function and Reproductive Health

The thyroid is essential for reproductive health and fertility, especially in women. Thyroid hormones help regulate menstrual cycles. Insufficient thyroid levels can lead to irregular, heavy, painful, or missed periods.

Thyroid disorders are a common cause of infertility issues and have been linked to an increased risk of miscarriage. For pregnant women, thyroid health is critical for fetal brain development in the early stages of pregnancy.

In men, hypothyroidism has been associated with erectile dysfunction and ejaculatory disorders. Hyperthyroidism could also potentially impact testosterone levels and sperm production.

Overall, both hypothyroidism and hyperthyroidism can disrupt reproductive hormones and cause conception problems in women and men. Having healthy thyroid function improves the chances of fertility.

Thyroid Hormones Influence Heart Health

Your thyroid impacts your heart rate, blood pressure, and cholesterol levels – all key indicators of cardiovascular health. Thyroid hormones boost heart rate and contraction force while relaxing blood vessels.

In hypothyroidism, decreased thyroid hormone leads to a slower heart rate and weakening of the heart muscle over time. High cholesterol levels are also common, increasing heart disease risk.

Conversely, too much thyroid hormone causes a rapid or irregular heart rhythm. This effect on heart rate and blood pressure increases the risk of atrial fibrillation in people with hyperthyroidism.

By regulating metabolic processes that influence heart function and cholesterol production, the thyroid gland directly affects heart health. Managing thyroid disorders can improve cardiovascular outcomes.


Thyroid Impacts Muscle Mass and Function

Thyroid hormones play a role in muscle growth and development, as well as muscle repair after injury or exercise. The hormones help stimulate protein synthesis – the process of generating new muscle proteins.

Low thyroid hormone levels lead to reduced muscle mass, strength, and function. Symptoms may include muscle weakness, soreness or cramping, and limited mobility.

On the other hand, hyperthyroidism could potentially weaken muscle tissues over time due to increased protein breakdown. However, the associated increase in metabolism may enhance athletic performance in the short term.

Overall, keeping thyroid levels in the normal range supports developing and maintaining healthy muscle mass and function. Addressing thyroid problems can improve muscle strength and reduce injury risk.

Regulating Body Temperature

The thyroid helps control thermoregulation – your body’s ability to regulate and maintain its internal temperature. Thyroid hormones boost heat production and increase your metabolism. This helps raise body temperature when needed to counteract cold environments or fevers.

In hypothyroidism, reduced thyroid hormone levels can disrupt normal thermoregulation. Sufferers often feel cold all the time, with cold hands and feet. They may be more sensitive to lower temperatures compared to those without thyroid disorders.

On the other end of the spectrum, hyperthyroidism and overactive thyroid leads to increased heat production in the body. This results in feeling hot, sweating excessively, or having difficulty tolerating high temperatures.

Impacts on Mood and Mental Health

Thyroid disorders often have mental health implications. Depression, anxiety, irritability, mood swings, reduced concentration, and memory issues are common symptoms.

Research has shown a higher prevalence of depressive symptoms in hypothyroid patients, with some studies reporting rates as high as 60%. Similarly, hyperthyroid patients have been found to have a higher prevalence of anxiety.

Researchers are still investigating the mechanisms behind the thyroid-mental health link. However, treating thyroid disorders often helps alleviate associated neuropsychiatric symptoms.

Final Thought

Maintaining proper thyroid function is essential for overall well-being. By getting evaluated and seeking treatment for thyroid disorders, you can get your metabolism, energy, body temperature, and other processes regulated. With healthy thyroid levels, your body and mind will be better equipped to perform at their best.


Thyroid gland

Thyroid and parathyroid glands

Thyroid and male reproduction – PMC

TSH cut off point based on depression in hypothyroid patients | BMC Psychiatry

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