Palpitations are a significant symptom of which thyroid disorder?

Palpitations are often associated with hyperthyroidism due to the increased metabolism and heightened levels of thyroid hormones that can stimulate the heart. In hyperthyroidism, the excess thyroid hormones lead to an increased heart rate (tachycardia) and can cause feelings of rapid or irregular heartbeats, which are experienced as palpitations. This condition can arise from various causes, such as Graves' disease or toxic nodular goiter, where the thyroid gland produces excessive hormones.

In contrast, hypothyroidism typically results in a slower heart rate (bradycardia) and is not usually associated with palpitations. Instead, it can lead to symptoms such as fatigue, weight gain, and depression, but does not heighten heart activity in a way that would produce palpitations. Hence, palpitations are a clear clinical sign connected to hyperthyroidism but not to hypothyroidism.