Hyperthyroidism manifestations: signs to know

The thyroid makes hormones that influence how quickly the body uses energy. When hormone levels are too high, you may feel unusually warm, sweat more than expected or lose weight despite eating normally. Some people notice trembling, muscle weakness, frequent bowel movements or a restless feeling. A racing, pounding or irregular heartbeat may occur alongside nervousness and difficulty sleeping. Symptoms can build gradually, so changes may be easier to recognise when you compare them with your usual pattern.

Arrange a medical assessment if several of these changes persist or interfere with daily activities. A clinician may ask about symptoms, medicines and supplements, examine your neck and pulse, and request thyroid blood tests. Keep a brief record of your resting heartbeat, bowel changes, sleep, sweating and weight trend. Do not start iodine products or alter prescribed treatment without advice. Read more about [Hyperthyroidism](/conditions/hyperthyroidism/) and related symptoms such as [Palpitations](/symptoms/palpitations/) or [Heat Intolerance](/symptoms/heat-intolerance/).

Seek urgent medical help for chest pain, fainting, severe breathlessness, confusion, marked agitation, or a very fast heartbeat that does not settle. Fever with severe weakness, vomiting or diarrhoea can also require prompt assessment, particularly if hyperthyroidism is known or suspected. These symptoms can have causes other than the thyroid, so do not wait for a routine appointment.

Ask which symptoms fit an overactive thyroid, which blood tests are needed, whether any medicine or supplement could be contributing, and how you should monitor your pulse while awaiting results.