If a patient experiences a rapid heartbeat after exercise, this is actually a relatively normal occurrence. A person may have a faster heartbeat when exercising, when he or she is emotionally excited, or when he or she has a fever, a cold, or is unwell. Generally speaking, for every 1°C increase in body temperature, the heart rate may increase by about 12 beats per minute, so the heart rate is not constant, it is affected by many factors. It is recommended that patients undergo an ambulatory electrocardiogram if necessary to help assess the overall 24-hour average heart rate and the presence of arrhythmias. If the patient’s heart rate is still fast even at rest, it is important to find out whether the patient has hyperthyroidism, anemia, or ionic disorders.