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An estimated 6% of the American population has thyroid disease. Of that percentage, nearly 80% have hypothyroidism. The thyroid produces too little thyroid hormone in this condition, causing the body systems to slow down.
The thyroid gland regulates your metabolism, growth, and development. The thyroid produces and releases thyroid hormone into your bloodstream to communicate this vital information to your organs. When the thyroid cannot produce enough thyroid hormone, organs like your heart begin to operate at a slower pace.
Thyroid hormone affects your heart in several ways.
When thyroid hormone levels are low, it can cause your heart rate to slow. A slower heart rate can decrease tissue perfusion, fatigue, and low energy.
Thyroid hormone also affects the elasticity of your blood vessel walls. When you don't make enough thyroid hormone, your arteries become less elastic. This means your arteries harden, and it is harder to get blood flow to your tissues. To compensate, your blood pressure must increase to perfuse all of your organs. Thus, people with hypothyroidism tend to have hypertension (high blood pressure).
Low thyroid hormones may also contribute to elevated cholesterol levels. When cholesterol levels are high, it can cause your arteries to become narrow and hardened. As you may imagine, when your cholesterol levels are high for an extended time, it can increase your risk for adverse cardiac events, including heart attack.
People with hypothyroidism are more prone to retaining fluid and having edema (swelling). When people start treatment for hypothyroidism, they often lose at least five pounds caused by fluid retention.
When your body has excess fluid, it places stress on your heart because it must work harder to pump throughout your body. Additionally, excess fluid can stress out your kidneys, as they are highly sensitive to increased pressure.
As we have seen, the thyroid directly affects the cardiovascular system. Thus, when your thyroid function is off, it can lead to heart problems or cardiovascular disease.
We know that high blood pressure, high cholesterol, and irregularities in your heart rhythm are risk factors for serious cardiovascular events, including:
- Myocardial infarction (heart attack)
- Stenosis of the heart valves
- Atrial fibrillation
- Heart failure
- Sudden cardiac arrest
According to the American Thyroid Association, severe hypothyroidism can lead to heart failure and death.
Hypothyroidism is not the only thyroid condition that can affect the cardiovascular system. An overactive thyroid (hyperthyroidism) can cause the production of too much thyroid hormone, which can also have severe consequences on your heart, including a rapid, irregular heart rate and congestive heart failure.
Hypothyroidism is a risk factor for heart disease. Fortunately, treating hypothyroidism with thyroid hormone replacement therapy may reduce your cardiovascular symptoms that could increase your risk for heart disease, including fluid retention, hypertension, and high cholesterol.
One study of patients in Denmark found that people with mild, untreated hypothyroidism had an 83% increased risk of having heart problems than people who did not have hypothyroidism or those receiving treatment. The takeaway from this study is that if you have hypothyroidism and are not treating it, you are three times more likely to develop heart problems.
Suppose you have cardiovascular symptoms associated with your hypothyroidism. In that case, it may be beneficial to meet with a cardiologist and your thyroid doctor. Along with thyroid medication, you may also require cardiac medications like anti-hypertensives and cholesterol-lowering medications to reduce your risk for heart disease.
Intriguingly, people with hypothyroidism often struggle to take statins, a class of cholesterol-lowering medications. One of the more common side effects of these medications is statin-induced myopathy or muscle pain.
Research suggests that an overwhelming number of people with statin-related myalgias also have hypothyroidism. Some experts believe that treating hypothyroidism can reduce and even relieve statin-induced myopathy. This is especially beneficial for hypothyroid patients, who already have myopathy as a symptom of their thyroid disorder.
By treating your thyroid, you may also improve your cardiovascular health because you may tolerate cholesterol-lowering medications better.
Are there other foods or drugs to avoid while taking cholesterol-lowering medications?
Talk to your healthcare provider about any other medications you take, including herbals and vitamins, and their impact on cholesterol-lowering drugs. It would help if you did not drink grapefruit juice while taking some types of cholesterol-lowering medications. It can interfere with the liver's ability to metabolize these medications.
Levothyroxine, or T4, is typically the first-line treatment for overt hypothyroidism. This medication is a synthetic form of thyroxine (T4) that mimics the thyroid hormone in the human body. In patients with hypothyroidism, levothyroxine can help reduce the risk of heart disease.
However, people with subclinical (or mild) hypothyroidism who have heart problems do not always benefit from thyroid medication. Too much levothyroxine can lead to hyperthyroidism, which can exacerbate heart issues. Indeed, there is a potential risk of causing more harm than good, especially in people with subclinical hypothyroidism and heart failure.
We know that thyroid medication is highly effective in managing hypothyroidism and preventing conditions that may lead to heart disease. Connect with your healthcare provider to make sure you are optimizing your thyroid and whole-body health.