Your Thyroid And Breathing: What’s The Link?

Overview

The thyroid is an endocrine gland found in your neck. Endocrine glands are responsible for producing hormones that are released into the blood. The thyroid hormone is mainly responsible for controlling your body’s metabolism, which essentially is the sum of chemical reactions that occur in your body, including those transforming food into energy. 

This energy is used throughout your body to keep your systems working effectively. Consequently, thyroid hormones exert a meaningful and vital effect all over the body. 

What are the main thyroid problems?

Problems with the thyroid include complications that influence hormone production. Because of the widespread effects of the thyroid gland, diseases of the thyroid affect the whole body. These include the following:

Goiter 

This condition refers to an enlargement of the thyroid gland. It is commonly caused by iodine deficiency. It can result in too much or too little thyroid hormone production. Goiter can be caused by both Hashimoto’s and Graves’ diseases. 

Thyroiditis 

This occurs due to the inflammation of the thyroid gland. It can also cause excessive or insufficient thyroid hormone production. 

Hashimoto's disease 

This is an autoimmune condition and a type of thyroiditis. In this case, thyroid cells are destroyed by the body, resulting in insufficient thyroid hormone production and chronic inflammation. 

Graves’ disease 

This is also an autoimmune condition in which antibodies act as thyroid-stimulating hormone receptors (TSHR), inducing thyroid cells to secrete excess thyroid hormones.

Thyroid nodules 

These are solid or fluid-filled clumps of cells that grow on the thyroid. They are often benign but must be surgically removed if suspected of being malignant. 

Hypothyroidism vs. hyperthyroidism

All conditions above can induce hyperthyroidism or hypothyroidism.

Hyperthyroidism occurs when excess circulating thyroid hormones are present. Overall, this makes your body consume energy faster, leaving you tired, increasing your heart rate, and potentially leading to weight loss. 

Hyperthyroidism can vary in severity but can be life-threatening if left untreated in more acute cases. Graves’ disease is responsible for around 60–80% of cases of hyperthyroidism.¹

Hypothyroidism refers to thyroid hormone deficiency and is ten times more common in women. In this instance, your body often does not tolerate cold temperatures, and you feel tired. If left untreated, hypothyroidism can lead to severe health complications or death.²

What causes thyroid problems?

Thyroid problems can be divided into hypothyroidism and hyperthyroidism, each of which has a variety of causes. 

A key component of the thyroid hormone is iodine. Consequently, iodine deficiency is a significant cause of hypothyroidism.

Hypothyroidism can also be caused by surgery as part of cancer therapy.³

Autoimmune conditions can cause different thyroid problems, in which the body produces antibodies that attack the cells in the thyroid. This can either result in hypothyroidism or hyperthyroidism.

Inflammation can cause problems with the thyroid and can be worsened by thyroid complications. 

Who is at risk of thyroid problems?

Problems with the thyroid can happen to anyone at any age. Nevertheless, the prevalence of thyroid disease increases with age, so older age may put you at higher risk.⁴

Genetic predisposition can result in Graves’ disease and Hashimoto’s thyroiditis. Women are also more at risk for these diseases. The precise reason for women having a higher incidence of thyroid problems is unknown. However, it’s thought to be related to estrogen and progesterone.⁵ ⁶ ⁷ ⁸

Iodine deficiency is a risk for developing thyroid problems. It is especially true in Southeast Asia, Africa, and the Western Pacific. Some of these geographic areas have iodine supplements available to lower this risk or have food fortified with iodine.⁹

While the pathological mechanism linking thyroid problems to diabetes is not fully understood, diabetes is closely linked to thyroid problems. Autoimmune thyroid problems occur in around 17–30% of people with type 1 diabetes, suggesting a link between these two endocrine disorders.¹⁰

Some endocrine disruptors, which include any chemicals that interfere with the body’s hormone system, can cause issues with the thyroid. Sunitinib, pembrolizumab, and ipilimumab are all used for cancer therapy and can lead to swelling of the thyroid, resulting in hypothyroidism or hyperthyroidism.¹¹

People with bipolar disorder undergoing lithium treatment may also develop a thyroid condition. Lithium inhibits thyroid function and can lead to hypothyroidism.¹²

What are the main symptoms of a thyroid disorder?

The key symptoms of hyperthyroidism include: 

• Tachycardia (increased heart rate)

• Palpitations 

• Weight loss 

• Tremors

• Anxiety

• Disturbed sleep

• Intolerance to heat

• Polydipsia (excessive thirst)

The key symptoms of hypothyroidism include: 

• Lethargy

• Cold intolerance

• Fatigue

• Weight gain

• Constipation

• Dry skin

• Change in voice (for example, roughness, low voice, limited vocal range)

• Fluid retention/swelling 

The link between the thyroid and the respiratory system

Your respiratory system involves anything that helps you breathe. This means it’s composed of your nose, throat, larynx, trachea, bronchi, and lungs. 

Because the thyroid hormones impact metabolism, they affect heart rate, blood volume, and heart contractility. Consequently, these all affect your breathing.¹³

Untreated hyperthyroidism and respiratory disorders

Hyperthyroidism can also lead to hyperventilation.¹⁴

Untreated hypothyroidism and respiratory disorders

Hypothyroidism can lead to dyspnea (shortness of breath). This may be partially due to the lack of thyroid hormone, causing a slowing of your heart rate. Shortness of breath due to compression of your upper airways caused by excess fluid retention is also of concern.¹⁵ ¹⁶

Maximal inspiration and expiration are decreased in hypothyroidism and are associated with its severity.

Your diaphragm muscles can become weakened, which can cause breathing problems over time. 

Sleep apnea is quite common in people with hypothyroidism. It leads to breathing repeatedly, stopping, and starting while sleeping.¹⁷

Hypothyroidism can lead to pleural collections in which excess fluid collects in the fluid-filled cavity lining outside the lungs. This occurs in around 25% of cases and often doesn’t show symptoms.¹⁸

Association between thyroid function and acute exacerbation of chronic obstructive pulmonary disease

Chronic obstructive pulmonary disease (COPD) is the name used to refer to a group of conditions that affect the lungs and induce subsequent breathing difficulties. The main cause of COPD is smoking.

Problems with thyroid function are common in COPD and can result in the worsening of COPD symptoms. The exact relationship between thyroid dysfunction and COPD is still being studied.¹⁹

Assessment of functional lung impairment in patients with thyroid disorders

Thyroid disorders, such as hypothyroidism and hyperthyroidism, can significantly impact lung function. Some methods are used to assess functional lung impairment in people with thyroid disorders. These include:

Spirometry is a regular test to assess lung function. It investigates how much air you inhale and exhale and how quickly you exhale. 

Maximal exercise testing can be used to investigate how much exercise you can tolerate. When you have thyroid complications, exercise can be more difficult. 

Arterial blood gas may also be recorded, indicating oxygen and carbon dioxide levels in the blood. 

By assessing lung impairment in thyroid disorders, your doctor can intervene as early as possible and determine if treatment is required.

The lowdown

The thyroid is an endocrine gland that plays a vital role in controlling our metabolism. Thyroid dysfunction can appear in several ways, leading to excess or too little thyroid hormone secretion. Both of these changes can affect our respiration, and in some cases, treatment is required, depending on the severity. 

Treatment is available for both hypothyroidism and hyperthyroidism. If you’re experiencing some symptoms or are concerned you might be at risk, talk to your doctor about what might be best for you. 

Frequently asked questions

Does the thyroid regulate breathing?

Thyroid hormones control your breathing and heart rate. However, the thyroid is one of the many components responsible for controlling your breathing. Your brainstem is actually the key point of breathing regulation.

Can thyroid problems cause low oxygen levels?

One role of thyroid hormones is to promote oxygen delivery to tissues. So, if you have low thyroid hormone levels (hypothyroidism), your tissues may have low oxygen levels.