The thyroid gland plays an important role in regulating metabolism, heart rate and many other body functions. When the thyroid produces too little or too much hormone, it can also affect blood pressure.
According to Harvard Health, both an underactive thyroid, known as hypothyroidism, and an overactive thyroid, known as hyperthyroidism, can be associated with elevated blood pressure.
How Hypothyroidism Affects Blood Pressure
Hypothyroidism occurs when the thyroid gland does not produce enough thyroid hormone. People with untreated hypothyroidism often have a higher diastolic blood pressure, which is the lower number in a blood pressure reading.
In some cases, both systolic and diastolic readings may increase. Treating hypothyroidism with thyroid hormone replacement can help bring blood pressure readings down. However, blood pressure may not completely return to normal because high blood pressure can have several causes.
Untreated hypothyroidism can also cause significant increases in blood cholesterol levels. Treating the thyroid condition can help lower cholesterol as well.
How Hyperthyroidism Affects Blood Pressure
Hyperthyroidism occurs when the thyroid gland is overactive and produces excessive thyroid hormone. This speeds up the body’s metabolism and can cause the heart to beat faster.
As a result, systolic blood pressure, the upper number in a blood pressure reading, can rise. Diastolic pressure generally remains unchanged or may decrease slightly.
Treatment that reduces excessive thyroid hormone production can lower heart rate and systolic blood pressure.
What This Means for People With High Blood Pressure
Thyroid problems are not the only possible cause of high blood pressure. However, because thyroid function can influence blood pressure, people with thyroid disorders may need their blood pressure monitored regularly.
If blood pressure remains high despite treatment, doctors may need to look for other contributing factors rather than assuming the thyroid condition is solely responsible.
When to Talk to a Doctor
Anyone diagnosed with a thyroid condition should follow their treatment plan and attend recommended checkups. Persistent high blood pressure should also be discussed with a healthcare professional.
Blood pressure and thyroid problems can occur together, and treating an underlying thyroid disorder may improve blood pressure in some people.
The Bottom Line
Yes, thyroid conditions can affect blood pressure. Hypothyroidism is often associated with higher diastolic pressure, while hyperthyroidism can raise systolic pressure by increasing heart rate and metabolism.
Proper diagnosis and treatment of thyroid disorders may help improve abnormal blood pressure readings, but high blood pressure can have multiple causes and should be evaluated separately when necessary.
