Exercise and a Healthy Heart

Your incredible heart

Right now, without you doing anything, your heart is beating. It has been beating since before you were born, and it will keep going your whole life. The heart is a muscle, about the size of your closed fist, and its job is to pump blood around your body.

That blood is a delivery service. It carries oxygen from your lungs and fuel from your food to every single one of the trillions of cells in your body. It also carries away waste. Without this constant delivery, your cells could not work, not even for a few minutes. So a healthy heart is one of the most important things you can have, and the amazing news is that exercise makes it stronger.

How the heart works

Your heart sits in the middle of your chest, tilted slightly to the left. It has four chambers and works like two pumps side by side:

• One side pumps blood that is low on oxygen to your lungs, where it picks up fresh oxygen.
• The other side pumps that oxygen-rich blood out to the rest of your body.

This whole loop is called your cardiovascular system (cardio means heart, vascular means blood vessels). The blood travels through tubes called arteries, veins, and tiny capillaries. If you want to dig deeper into the partnership between the heart and lungs, see how the heart and lungs work in exercise.

Why exercise strengthens the heart

Here is the key idea: the heart is a muscle, and muscles get stronger when you use them.

When you do aerobic exercise, your muscles demand more oxygen, so your heart has to beat faster and harder to deliver it. The word aerobic means "with oxygen". Examples include:

• running and jogging
• swimming
• cycling
• fast walking
• dancing
• many team sports like football and basketball

Doing this regularly, over weeks and months, trains your heart just like lifting weights trains your arms. The heart muscle becomes bigger and stronger, and each beat pumps out more blood. This ability is called cardiovascular fitness or stamina.

The sign of a strong heart: a slower resting beat

Here is something that surprises a lot of people. A fitter heart usually beats more slowly when you are resting, not faster.

Why? Because a strong heart pushes out more blood with each beat. If every beat does more work, the heart does not need to beat as often to deliver the same amount of blood. So your resting heart rate drops.

A typical resting heart rate for a young person might be around 70 to 100 beats per minute, while very fit athletes can have resting rates well below 60. So a low resting heart rate is often a sign of a well-trained heart. You can learn how athletes use this idea in understanding heart rate zones.

Why a healthy heart matters for life

A strong heart does not just help you in sport. It protects your health for your whole life. Regular exercise:

• lowers the risk of heart disease later in life
• helps keep blood pressure healthy
• helps your blood vessels stay clear and flexible
• improves how well your whole body uses oxygen
• supports a healthy body weight and mood

Heart disease is one of the biggest health problems for adults around the world, and habits built when you are young make a real difference. Being active now is an investment in your future heart.

How much exercise do you need?

Health guidelines suggest that most children and teenagers aim for at least 60 minutes of moderate-to-vigorous activity a day. That does not have to be done all at once. It can be:

• cycling or walking to school
• playing at break time
• a sports practice
• dancing or playing in the garden

The activity that helps your heart most is the kind that gets you breathing faster and your heart pumping. Building this into everyday life is the goal, as explained in staying active every day.

Activity: the heart-rate experiment

You can actually feel your heart respond to exercise. Try this safe experiment with a clock or stopwatch.

1. Find your pulse. Place two fingers (not your thumb) gently on the side of your neck or your wrist until you feel a steady beat.
2. Measure resting heart rate. Sit calmly for a minute, then count the beats for 15 seconds and multiply by 4. Write the number down. That is your beats per minute (bpm).
3. Exercise. Do one minute of star jumps, jogging on the spot, or fast skipping.
4. Measure again. Straight away, count your pulse for 15 seconds and multiply by 4. Notice how much higher it is!
5. Recovery. Rest and measure once a minute. See how long it takes to return near your resting number.

What to notice: Your heart rate jumps up during exercise because your muscles need more oxygen. Over weeks of regular training, you may find that your heart rate returns to normal faster after exercise, and your resting rate gets a little lower. Both are signs your heart is getting fitter.

Safety note: a pounding heart during exercise is normal. But if you ever feel chest pain, dizziness, or faint, stop and tell an adult.

Every time you run, swim, cycle, or play, you are giving your heart a workout. Look after it, and it will look after you for a lifetime.