What exercise does to your body

Physical activity makes your heart, lungs and muscles work harder. Learn the different kinds of activity, the talk test for effort, how much activity you need, and run a fair test on your pulse.

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Physical activity is any movement of your body made by your muscles that uses energy. Exercise is a planned, structured kind of physical activity.[2][4]

Children and young people aged 5 to 18 should aim for an average of at least 60 minutes of moderate or vigorous activity a day across the week, with a variety of activities to build movement skills, muscles and bones.[1]

The talk test: moderate activity raises your heart rate, makes you breathe faster and feel warmer, but you can still talk (not sing). In vigorous activity you can't say more than a few words without stopping for a breath.[1][5]

There are different kinds of activity. Aerobic activity (running, cycling, skipping) makes your heart beat faster and you breathe harder. Muscle-strengthening activity (push-ups, sit-ups, climbing) makes muscles stronger. In bone-strengthening activity (running, jumping) your muscles push against your bones and make them stronger.[5]

Regular activity builds strong muscles and bones, improves fitness, helps attention and memory and reduces the risk of diseases such as type 2 diabetes.[3]

Many young people are not active enough: the WHO reports that 86% of adolescents worldwide do not meet the recommended levels of activity.[2]

Try it: Pulse fair test: does harder activity raise your heart rate more?

⏱ 35 minutes

You need

A stopwatch or the classroom clock
Space to move safely
The record table

Safety

Leave space between pupils and use a non-slip floor. Pupils with a health condition follow their care plan and can be the timekeeper instead. Anyone who feels dizzy, unwell or in pain stops and tells the teacher. Pulse results are personal: no comparing or competing.

What to do

Find your pulse on the inside of your wrist (below the thumb) with two fingers. Count the beats for 15 seconds and multiply by 4 to get beats per minute. This is your resting pulse.
Walk on the spot for 1 minute, then measure your pulse straight away.
Rest until your pulse is back near your resting value.
Jog on the spot for 1 minute and measure again. Rest again.
Do star jumps for 1 minute and measure again.
Fair test: keep each activity the same length, measure the same way each time, and rest until your pulse is back to resting before the next activity. Which activity raised your pulse most?

What happens, and why?

Harder activity makes your muscles work harder, so they need more energy and more oxygen. Your heart pumps faster to deliver it, so your pulse goes up more for more vigorous activity, and you breathe harder too. When you rest, your pulse comes back down.[5][6][7]

Play: What kind of activity?

Each activity mainly belongs to one kind. Is it aerobic, muscle-strengthening, or balance and flexibility?

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Quiz

Other ages: Ages 6–7 · Ages 15–16