What should you know about chills and heart palpitations?

A surge of stress hormones can cause trembling and a pounding or fluttering heartbeat. Dehydration, fever, anaemia, or low blood sugar can also make the heart feel more noticeable. Hyperthyroidism may cause heat intolerance, tremor, weight change, and a fast pulse. Some people with generalised anxiety disorder experience repeated episodes, while an irregular rhythm such as atrial fibrillation can cause palpitations that start and stop or remain uneven.

Note whether the beat feels fast, irregular, or forceful; how long it lasts; what you were doing; and whether dizziness, breathlessness, fever, or medication changes occurred. A clinician may check your pulse, blood pressure, an ECG, and blood tests.

Sit or lie down, loosen tight clothing, and breathe slowly. Avoid driving, caffeine, nicotine, and strenuous activity until the episode settles. Sip fluids if dehydration is possible. If you have diabetes and can safely check your glucose, follow your personal low-glucose plan. Do not take someone else’s heart medicine or supplements.

Arrange an appointment when episodes recur, last longer than usual, occur during exercise, or come with tiredness, weight change, or swelling. Bring a list of medicines and a record of pulse readings if available.

Call emergency services for palpitations with chest pain or pressure, severe breathlessness, fainting, new confusion, or marked weakness. Urgent assessment is also appropriate for a sustained very fast or irregular heartbeat, especially if you feel light-headed. People with known heart disease, pregnancy, or a history of rhythm problems should seek advice promptly when symptoms are new or changing.

Ask: Is my rhythm regular? Could dehydration, anaemia, thyroid disease, or glucose changes contribute? Do I need an ECG or blood tests? Which symptoms mean I should call emergency services?