Hypothryoidism and Heart Disease

Fact Sheet

Hypothyroidism and Heart Disease

  • Editors
  • Alan Farwell, MD

    James V. Hennessey, MD

    Leonard Wartofsky, MD

What is the thyroid gland and what does it do?

The thyroid gland, located in your neck, makes two kinds of thyroid hormones: T4 (thyroxine) and T3 (triiodothyronine). Thyroid hormones regulate how your body uses and stores energy. These hormones also help your brain, heart, muscles, and other organs work properly. They affect your breathing, nervous system, body temperature, and weight.

What is hypothyroidism and what are its symptoms?

Hypothyroidism, also called an underactive thyroid, occurs when your thyroid gland makes too little thyroid hormone. When you don’t have enough thyroid hormone, you won’t feel well and can have health problems.

Did You Know?

Hypothyroidism is more common in women and in people older than age 50.

Symptoms include

These symptoms can occur with other health problems as well.

Thyroid Gland

Thyroid gland

How is hypothyroidism diagnosed?

Your doctor diagnoses hypothyroidism by doing a physical exam and asking you about your symptoms. The doctor will look at results of blood tests of your hormone levels before making decisions about treatment.

What is the treatment for hypothyroidism?

The goal of treatment is to make sure you have normal levels of thyroid hormone all of the time. People who have hypothyroidism must take a pill containing thyroid hormone every day to replace the hormone they lack. The most common thyroid hormone treatment is levothyroxine, a synthetic (manufactured) form of T4. Levothyroxine is exactly the same as the T4 made by the body and it works the same way as your own thyroid hormone.

Why does hypothyroidism increase your risk for heart disease?

Both thyroid hormones (T4 and T3) are related to heart disease because they affect your heart rate and the amount of blood pumped by your heart. Thyroid hormones help your blood flow smoothly by relaxing the muscles of your blood vessels and keeping your blood vessels open.

Hypothyroidism also can lead to increased levels of LDL (“bad”) cholesterol, total cholesterol, triglycerides, and other fats related to heart disease.

What serious problems can happen if I have heart disease?

Rare but serious problems can include

You can also have a very slow heart rate and irregular heartbeats.

What kinds of heart-related problems can happen with hypothyroidism?

You can have

Heart problems can even occur with mild hypothyroidism (called subclinical hypothyroidism).

What can I do to take care of heart-related problems?

Make sure you see your doctor regularly for checkups and checks of your blood pressure. Get medical tests as recommended, such as a blood test to check cholesterol levels. Ask your doctor if you need medicines for heart problems. See a registered dietitian for diet advice if needed.

What are my long-term prospects with hypothyroidism?

Hypothyroidism is a lifelong condition, but taking thyroid hormone pills every day can prevent related health problems, such as heart problems. You should get a checkup at least once a year to make sure your dose of thyroid hormone is still right for you.

Questions to ask your doctor