Hyperthyroidism means the thyroid gland is overactive and makes too much thyroid hormone. This can speed up many body functions.
Common symptoms
Symptoms can include weight loss, fast heartbeat, palpitations, anxiety, tremor, sweating, heat intolerance, trouble sleeping, diarrhea, or menstrual changes.
Why it matters
Too much thyroid hormone can affect the heart, bones, muscles, mood, and metabolism. In some people, it can contribute to atrial fibrillation or other heart rhythm problems.
Hyperthyroidism is diagnosed with blood tests and sometimes imaging or antibody testing, depending on the suspected cause.