Can hyperthyroidism cause hypertension?

Excess thyroid hormone increases the body's response to adrenaline. The heart may beat faster and pump more blood with each contraction, while blood vessels may respond differently. This can widen the difference between the upper and lower blood-pressure readings. It does not mean every person with hyperthyroidism develops hypertension, and high blood pressure has many possible causes. A racing pulse, excessive sweating, heat intolerance, poor sleep or feeling anxious can occur at the same time. Learn more about [Hyperthyroidism](/conditions/hyperthyroidism/).

Have your blood pressure checked properly, ideally with repeated readings taken when you are rested. Tell the clinician about palpitations, headaches, breathlessness, thyroid symptoms, prescribed medicines and supplements. Thyroid blood tests can show whether hormone excess is present; an examination may identify other contributors to raised pressure. Take prescribed blood-pressure or thyroid medicine as directed, and do not stop either without medical advice. Reducing stimulant drinks may be sensible if they worsen palpitations, but it cannot replace assessment.

Seek emergency help for chest pain, severe breathlessness, fainting, new weakness on one side, trouble speaking, confusion or a severe headache with very high blood pressure. A persistently racing or irregular heartbeat also warrants prompt care. If readings are repeatedly elevated without severe symptoms, arrange a medical appointment so both thyroid activity and blood pressure can be reviewed.

Ask whether thyroid testing could explain your readings, whether home monitoring would help, and whether your current medicines or supplements affect blood pressure. Clarify the target readings for you and when a result should prompt urgent help.