Fast heart rate may be caused by physiological factors, thyroid disease, heart disease, anemia, etc. It refers to the phenomenon that the heart beats more than 100 times per minute. 1. Physiological factors: A fast heart rate can be caused by physiological factors, such as a change in body position or strenuous physical activity, or lack of sleep. A rapid heart rate can also occur as a result of an uncontrolled diet. Eating a lot of stimulating foods or drinking beverages that contain a lot of caffeine and alcohol can lead to a fast heart rate. In addition, over-excitement, nervousness or fear may increase the heart rate. 2. Thyroid disease: when suffering from thyroid disease such as hyperthyroidism, due to the body’s basic metabolism increases, sympathetic nerve excitation and other reasons, it will affect the heart function, a rapid heart rate of a kind of adverse reactions. 3. Heart disease: many heart diseases can lead to fast heart rate, such as angina pectoris, myocardial infarction and myocarditis, cardiomyopathy and other heart diseases, may be manifested as fast heart rate. There are also a variety of clinical conditions that can cause a fast heart rate, such as anemia and malnutrition. If your heart rate remains fast, or if you feel unwell, you should consult a doctor for examination and treatment.