How Your Thyroid Affects Your Heart Health

A thyroid disorder can cause or worsen cardiovascular disorders

Your thyroid, a butterfly-shaped organ that generates hormones that control your metabolism, sits low at the front of the neck. This very significant organ plays a role in controlling your body’s energy supply, and has a tremendous effect on your health, impacting all aspects of your metabolism. It can throw off your moods, make you feel unwell when it’s unstable, and transform daily activities into what feels like heroic efforts.

How the Thyroid Gland Works

The hormones produced by the thyroid regulate vital body functions such as heart rate, breathing, cholesterol levels, and much more.  

The thyroid gland determines how fast the body uses energy, produces proteins, and regulates how sensitive the body is to other hormones. It takes part in these processes by developing thyroid hormones, the major ones being triiodothyronine (T3) and thyroxine (T4). The thyroid also manufactures calcitonin. 

Disorders of the Thyroid Gland

Though there are many thyroid conditions that vary from being born with a non-functioning thyroid gland to iodine deficiency, the most common disorders will be covered.

Hyperthyroidism, an overactive thyroid, is a disorder in which elevated thyroid hormone levels are released into the body by the thyroid.

Hypothyroidism, an underactive thyroid, is a disorder in which the body doesn’t produce sufficient levels of thyroid hormones.

Graves’ Disease is an autoimmune disorder that causes hyperthyroidism. Your immune system attacks the thyroid and causes it to produce more thyroid hormones than your body requires.

Hashimoto’s Disease is an autoimmune disorder that causes hypothyroidism. Your immune system targets your thyroid and damages it to the extent where it can’t produce enough thyroid hormones.

Goiter is an enlarged thyroid gland that causes thyroid levels that are normal, excessive, or insufficient.

Nodules are solid or fluid-filled growths on the thyroid gland.

How Disorders of the Thyroid Affect the Heart

thyroid and blood pressure

High Cholesterol 

Often thought of as being caused by diet or lifestyle choices, sometimes thyroid disorders or other medical conditions are at fault for increased cholesterol levels. To generate cholesterol and eliminate the cholesterol it does not need, your body needs thyroid hormones. Your body doesn’t break down and remove LDL cholesterol effectively when thyroid hormone levels are low. 

Heart Rate

Excessive thyroid hormone increases the force of the heart muscle contraction and the amount of oxygen demanded by the heart. It also increases heart rate and the workload of the heart. Insufficient thyroid hormone causes the heart muscle to pump less vigorously, which can cause gradual weakening and the heart muscle’s inability to relax entirely after each heartbeat.

Blood Pressure

Most people would think that low thyroid hormone, since it slows everything down, would cause low blood pressure, but that is not the case. High blood pressure can result from not getting enough or too much of this hormone and across the entire spectrum of thyroid disease, blood pressure is altered.

Existing Cardiac Disorders

Cardiovascular conditions, including atrial and ventricular arrhythmias, atherosclerotic artery disease, dyslipidemia, and heart failure, may be caused or worsened by both thyroid hormone excess and deficiency.

In almost all cases, when the underlying thyroid disorder is recognized and treated, these cardiovascular changes are treatable and can be reversible.

Symptoms of Thyroid Dysfunction

thyroid fatigue

Hyperthyroidism – Overactive Thyroid

  1. Muscle weakness

  2. Rapid heartbeat

  3. Menstrual irregularity

  4. Feeling shaky, anxious

  5. Weight loss

  6. Increased appetite

  7. Difficulty sleeping

  8. Feeling tired

  9. Diarrhea 

  10. Mood changes

  11. Increased sweating

  12. Heat intolerance

Hypothyroidism – Underactive Thyroid

  1. Fatigue

  2. Muscle pain

  3. Weakness

  4. Constipation

  5. Weight gain

  6. Cold intolerance

  7. Dry skin

  8. Abnormal cholesterol levels

  9. Mood changes

  10. Brain fog

  11. Puffy face

  12. Menstrual irregularity

Your body runs faster than normal when you have hyperthyroidism, and it may feel like your heart is racing and you have a lot of nervous energy.  Your body works slower than usual when you have hypothyroidism, and it may seem as though you don’t have the same energy and strength you once had, although you’re sleeping well.


A thyroid panel is a series of tests that can be ordered together to help determine the function of the thyroid gland and to help diagnose thyroid disorders. The thyroid panel tests assess the amount of thyroid hormones in the blood and include TSH, Free T3, and Free T4. In the event of suspected autoimmune thyroid disease, thyroid antibody testing can confirm the diagnosis.  

Your doctor will explain your test results to you and if you have thyroid dysfunction, how it is treated, and the developments in thyroid disease diagnosis and management.