What should you know about hot and cold intolerance?

Temperature intolerance means feeling unusually uncomfortable in conditions that most people tolerate, such as needing extra layers in a mild room or becoming overheated easily. Hypothyroidism may cause cold intolerance alongside tiredness, dry skin, constipation, slowed thinking or weight change. Anaemia and iron deficiency anaemia can be associated with feeling cold, low energy or breathlessness. Heat sensitivity can also relate to fever, dehydration, medicines, hormones or the surrounding climate. The symptom does not identify one diagnosis by itself.

Note whether heat, cold or both cause symptoms, when the change began, and whether you also have tiredness, palpitations, sweating, bowel changes, skin changes or weight change. Keep fluids available in hot weather, use breathable clothing and avoid sudden extreme temperature exposure. Do not change prescribed thyroid medicine or start iron supplementation without clinical advice. A clinician may review your medicines, examine you and request blood tests to assess thyroid function or blood health.

Seek emergency care for confusion, fainting, severe weakness, chest pain, severe breathlessness, a very fast or irregular heartbeat, or inability to keep fluids down during heat exposure. Urgent help is also needed for a very low body temperature with drowsiness or poor coordination. Arrange a medical appointment when intolerance is persistent, worsening or accompanied by unexplained tiredness, major weight change, bleeding, tremor or palpitations.

Ask whether your symptoms warrant thyroid tests, a blood count or iron assessment; whether any medicine, supplement or hormone change could contribute; and how to manage heat exposure safely. Bring a symptom timeline and mention heavy periods, dietary restrictions, pregnancy and long-term conditions.