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Why Does Your Heart Beat Faster When You Run?

Put your fingers against your wrist or chest while you're sitting quietly. You should be able to feel a steady beat.

HUMAN BODY

9/15/20261 min read

heart illustration
heart illustration

Put your fingers against your wrist or chest while you're sitting quietly. You should be able to feel a steady beat.

Now imagine running across a playground as fast as you can. Your heart starts thumping much faster.

Why?

Your muscles need energy to move. To release that energy, their cells need oxygen and nutrients carried by your blood.

When you start exercising, your muscles demand more.

Your brain and body respond by telling your heart to pump faster and harder. This sends more oxygen-rich blood towards the working muscles. Your breathing speeds up too, helping your lungs bring more oxygen into your body and remove carbon dioxide.

Your heart is a muscular pump, and it works continuously throughout your life. Even while you're asleep, it keeps blood travelling around your body.

When you stop running, your muscles don't need quite as much oxygen anymore. Gradually, your breathing slows and your heart rate begins returning towards its resting level.

Try it: Count how many heartbeats you can feel in 15 seconds while resting. Try again after some gentle exercise. Is there a difference?

Your pounding heart isn't complaining about the exercise. It's responding to your body's changing needs.