Preparatory activities: First count the pulse and do 5 to 10 minutes of stretching and soft gymnastics to prevent damage to joints and muscles, while gradually increasing the heart rate so that the heart and lungs get warmed up. Aerobic exercise: count the pulse again and perform aerobic exercise for 15 to 30 minutes or longer, such as walking, jogging, cycling or swimming. Relaxation activities: Count pulses and perform 10 minutes of stretching and soft gymnastics to allow the heartbeat to slowly return to normal. It is not safe to stop suddenly while exercising. Count your pulse again at the end of exercise.