Heartbeat

Have you ever noticed that your heart beats faster when you do sport? Why does that happen? Well, the human heart normally beats between 60 and 100 times every minute. When you exercise, the heart beats must faster – up to 200 beats per minute. Your muscles need more oxygen, so the blood carries oxygen to the muscles. The muscles create more waste (like carbon dioxide and acid)
during exercise, so the blood carries it away.
Other things cause the heart to beat faster, too. Emotions like fear and anxiety make the pulse rate increase. Think about your reaction to a big dog barking at you. Your heart beats much faster so your body is ready to run away (but you should never run away from a dog, or it will chase you). Some medicines can make your heart beat faster, too. If you take medications for the common cold,
the flu or asthma, your heartbeat can increase.
Some people use their brains to slow down the speed of their heartbeat. A few Yogis in India say they can actually stop their heart by using meditation. I don’t think you should try to do this. If you are worried about your heartbeat, ask your mum and dad to call a doctor.