In this article

‍

Hypertension – also known as high blood pressure – affects as many as one in four people and is a significant global health concern. It’s estimated that around 10% of all cases of hypertension are the result of underlying illnesses including thyroid conditions. In this article, we look at the link between hypothyroidism and hypertension, and what thyroid patients need to know.  

‍

First, it’s helpful to understand the mechanics of blood pressure. Blood pressure is a measure of the force of your blood pushing against your artery walls. Blood pressure is written as two numbers, with the first number representing the systolic pressure and the second number representing the diastolic pressure. 

Systolic pressure is the pressure in your blood vessels when your heart contracts or beats. Diastolic pressure is the pressure in your blood vessels when your heart rests between beats. As you can imagine, your systolic number will always be higher than your diastolic.

According to most sources, including the Centers for Disease Control and Prevention: 

• Normal blood pressure is defined as levels below 120/80 mmHg
• Prehypertension is defined as systolic levels between 120-139 mmHg and diastolic between 80-89 mmHg. 
• Hypertension is defined as systolic levels of 140 mmHg or higher and diastolic levels of 90 mmHg or higher.

Physicians often focus specifically on elevated diastolic pressure levels, because they are more common, and a better predictor of heart disease. On their own, diastolic readings above 80 mmHg are sometimes considered evidence of “diastolic hypertension.” 

‍

Hypertension often produces no symptoms, but it can increase the risk of heart disease, stroke, heart failure, atrial fibrillation, peripheral arterial disease, vision loss, and chronic kidney disease. In rare and severe cases, high blood pressure can cause symptoms such as severe headaches, nosebleeds, fatigue, confusion, vision problems, chest pain, and difficulty breathing. However, most people with hypertension will experience no symptoms at all. 

‍

Hypertension is diagnosed by measuring blood pressure on two or more separate occasions. Blood pressure is measured using a sphygmomanometer, an inflatable cuff that is wrapped around the upper arm, and a pressure gauge that measures the pressure in the cuff.

Hypertension is diagnosed if the systolic blood pressure readings on both occasions are equal to or greater than 130 mmHg and/or the diastolic blood pressure readings on both days are equal to or greater than 80 mmHg. 

You may think you’re in the clear if your blood pressure readings at the doctor’s office are “normal.” But you should know that there’s also a condition known as “masked hypertension,” where your blood pressure readings are normal in a clinical setting but are elevated outside of the clinical setting, such as at home or during daily activities. It is the opposite of “white-coat hypertension,” where your blood pressure readings are elevated in a clinical setting but normal outside of the clinical setting. Masked hypertension is associated with an increased risk of cardiovascular disease, and it is important to detect and manage it to prevent further complications. You may want to ask your physician about the potential benefits of periodically testing your blood pressure at home to rule out the possibility of masked hypertension.

‍

Hypertension is not considered a typical sign of hypothyroidism, but experts are increasingly recognizing an increased risk of hypertension in people with subclinical or overt hypothyroidism. Similarly, it’s becoming better understood that hypothyroidism is a cause of secondary hypertension.

Secondary hypertension is a type of hypertension that is caused by an identifiable underlying primary cause. It is much less common than primary hypertension, which has no identifiable cause. Endocrine conditions, especially thyroid disease, are a common cause of secondary hypertension.

Specifically, studies have shown that diastolic hypertension is present in about 30% of patients with overt hypothyroidism. And the risk of diastolic hypertension is greatest in patients over 50.

One recent study also found that there’s a significantly higher prevalence of masked hypertension in patients with subclinical and overt hypothyroidism compared to the euthyroid (normal thyroid function) population.

Your Guide To The Genetics Of Thyroid Function

Knowing your risk for thyroid disease can help you stay in front of complications. Learn in this guide how genes impact your risk for hypothyroidism.

Thank you! Check your mailbox for your guide

Oops! Something went wrong while submitting the form.

‍

The mechanism of how hypothyroidism causes hypertension is not completely understood, but several factors have been implicated. Studies have shown that hypothyroidism can lead to:

• Increased peripheral vascular resistance is the resistance to blood flow in the peripheral arterial vessels. This is typically a function of the diameter of the blood vessels and the thickness of the blood. It is the resistance that must be overcome to push blood through the circulatory system and create flow
• Low cardiac output is a condition in which the heart does not pump enough blood to supply the body and tissues with the necessary oxygen and nutrients

‍

The treatment for primary hypertension depends on the severity of the condition and the presence of other medical conditions. First-line therapy for hypertension is lifestyle modification, consisting of weight loss, reducing the amount of sodium in the diet, and potassium supplementation. Other lifestyle changes that can help manage hypertension include regular exercise, quitting smoking, and limiting alcohol consumption. 

If lifestyle changes are not enough to manage hypertension, medications may be prescribed. Common medications for hypertension include diuretics, ACE inhibitors, angiotensin receptor blockers, calcium channel blockers, and beta-blockers. The choice of medication depends on the individual's medical history, age, and other factors. 

It's important to note that in patients who have abnormal thyroid function, these traditional approaches and medications used to lower blood pressure are usually ineffective. That’s why your healthcare provider needs to determine if you have secondary hypertension as a result of your thyroid dysfunction. 

In patients with secondary hypertension due to hypothyroidism, the good news is that optimal thyroid hormone replacement medication is often the best first-line treatment option. Studies have shown that elevated blood pressure in patients with overt hypothyroidism often returns to within the normal range after thyroid hormone replacement is started and the thyroid is well-controlled.

In patients with borderline or subclinical hypothyroidism, however, thyroid hormone substitution does not typically lower blood pressure, and interventions for primary hypertension need to be implemented along with optimal thyroid treatment. 

‍

Hypothyroidism is often overlooked as a potential cause of hypertension. And many patients and doctors aren’t aware of the increased risk of hypertension in patients with hypothyroidism.   

If you have hypertension, a complete thyroid evaluation and screening should be part of your regular healthcare routine. Ask your doctor to include a complete thyroid panel as part of your blood testing. Or, you can conveniently test your thyroid levels at home, with the Paloma Complete Thyroid Test kit.  

If you’re hypothyroid, make sure that you have regular blood pressure checks to identify hypertension, including masked hypertension. 

Also, it’s important to optimally manage hypothyroidism in patients with hypertension to prevent further complications. Consider working with Paloma’s thyroid-savvy healthcare providers for your thyroid care. Paloma’s practitioners are committed to helping you achieve total thyroid wellness and life-changing symptom relief.