Heart rate suddenly rises to 170, depending on the situation, sports, diseases, mental problems can cause heart rate increase. 1. Exercise: physiological reasons, such as some strenuous exercise, running 100 meters or playing basketball and other sports, at this time the heart rate can reach 170, usually after rest can be restored, do not need to be treated. 2. Diseases: such as atrial fibrillation, atrial tachycardia, supraventricular tachycardia and other arrhythmias, heart failure, hyperthyroidism, fever, anemia, etc. may appear fast heartbeat, this situation requires treatment to treat the primary disease. 3. Psychological factors: such as nervousness, panic, anxiety, or hysterical episodes or psychotic episodes may cause a sudden increase in heart rate. In either case, it is necessary to pay attention to the changes in heart rate and seek medical attention in time to avoid delaying the condition.