B. Active Living / C. Movement Competence · Active Living and Movement: Motivated, Fit, Safe and Skilful

How Fitness Works: Heart Rate and the Four Parts of Fitness

B2 A1.6About 40 minutes

Learning goals

I can find my heart rate in beats per minute by counting for 15 seconds and multiplying by 4.
I can compare my heart rate at rest and during activity and explain what it shows.
I can describe the benefits of activities that work my heart and lungs.
I can name the four parts of health-related fitness and an activity that builds each one.

Words to know

heart rate
How many times your heart beats in one minute.

bpm
Beats per minute: the unit we use for heart rate.

resting heart rate
Your heart rate when you have been sitting still and calm for a few minutes.

cardiorespiratory endurance
How long your heart and lungs can keep you moving without stopping.

muscular strength
How much force your muscles can make, like pushing or lifting something heavy.

muscular endurance
How many times, or how long, your muscles can keep working before they get tired.

flexibility
How far you can move and bend at your joints, like reaching toward your toes.

Remember from Grade 3

You learned that cardiorespiratory fitness means how well your heart and lungs keep you moving. You found your pulse at your wrist or neck and counted beats for 15 seconds. You saw that the count goes up when you work harder.

This year you will turn your count into a real heart rate, learn what cardio activities do for you, and meet the four parts of fitness.

From a count to a heart rate

Doctors and coaches talk about heart rate in beats per minute (bpm). One minute is 60 seconds. Counting for a whole minute takes a long time, and your heart starts slowing down when you stop moving. So here is a shortcut:

Count your pulse for 15 seconds.
There are 4 groups of 15 seconds in a minute (15 + 15 + 15 + 15 = 60).
So multiply your count by 4.

If you count 20 beats in 15 seconds, your heart rate is 20 × 4 = 80 bpm.

A minute is four groups of 15 seconds, so multiply your 15-second count by 4 to get beats per minute.

Finding your pulse

Use the first two fingers (not your thumb) on the thumb side of your wrist, or gently on one side of your neck. Press gently. A hand flat on your chest works too.

Heart rate at rest and while moving

Here is one student's heart rate at three times:

One student's heart rate in beats per minute (bpm): 84 resting, 108 after a fast walk and 152 after running. The 15-second counts were 21, 27 and 38.

Why cardio activities are good for you

Cardio activities make your heart and lungs work harder for a while: running games, skipping, biking, swimming, skating, dancing, cross-country skiing.

When you do them often, over weeks:

your heart gets stronger and can pump more blood with each beat, so it often beats more slowly at rest,
you can keep going longer before you need a break,
you recover faster after hard play,
you have more energy for the day, and many people sleep better and feel happier.

The four parts of health-related fitness

Being fit is more than running fast. There are four parts of fitness that help your health:

Part of fitness	What it means	Activities that build it
Cardiorespiratory endurance	Heart and lungs keep you moving for a long time.	Skipping, biking, swimming, tag, cross-country skiing
Muscular strength	Muscles can push, pull or lift with a lot of force.	Climbing on play structures, wall push-ups, carrying groceries with a grown-up, tug-of-war
Muscular endurance	Muscles can work many times, or for a long time, before getting tired.	Holding a plank, many curl-ups, paddling a canoe, a long bike ride
Flexibility	Joints and muscles can bend and stretch far.	Gentle stretches, yoga, gymnastics, dance

The four parts of health-related fitness.

Strength or endurance?

These two are easy to mix up. Ask: how many times?

Pushing a heavy snowball once to start a snowman is mostly strength (a lot of force, a few times).
Doing 20 wall push-ups in a row, or holding a plank for 30 seconds, is mostly endurance (many times, or a long time).

Many activities use more than one part. Swimming uses cardio endurance, muscular endurance and flexibility!

Worked example

Let's find a heart rate

After skipping rope, Zara counts 35 beats in 15 seconds. Before skipping, she counted 19. What are her heart rates in bpm? How much did her heart rate go up?

Before: 19 × 4. Think 20 × 4 = 80, then take away one 4: 80 − 4 = 76 bpm.
After: 35 × 4. Think 30 × 4 = 120 and 5 × 4 = 20. 120 + 20 = 140 bpm.
Compare: 140 − 76 = 64.
Why? Skipping is a cardio activity. Her muscles needed more oxygen, so her heart pumped faster.

Zara's heart rate went from 76 bpm to 140 bpm, up 64 bpm.

Worked example

Let's sort activities by fitness part

Which part of fitness does each activity build the most? (1) Holding a wall sit for 40 seconds. (2) Reaching toward your toes slowly. (3) A 20-minute bike ride. (4) Lifting a heavy box with a grown-up's help.

(1) A wall sit for 40 seconds keeps leg muscles working a long time: muscular endurance.
(2) Reaching toward your toes stretches muscles and joints: flexibility.
(3) A 20-minute bike ride keeps heart and lungs working a long time: cardiorespiratory endurance.
(4) Lifting something heavy needs a lot of force: muscular strength.

1 muscular endurance, 2 flexibility, 3 cardiorespiratory endurance, 4 muscular strength.

Hands-on activity

Four-part fitness sampler

You need: a timer, paper, a pencil, a wall and a grown-up.

Sit still for 3 minutes. Count your pulse for 15 seconds and multiply by 4. Write your resting heart rate.
Warm up for 3 minutes (marching, arm circles, easy jogging on the spot).
Do each station for 1 minute, with a 30-second rest between:

Cardio: jumping jacks or jogging on the spot.
Strength and endurance: wall push-ups (hands on the wall at shoulder height, feet back, bend and push).
Muscular endurance: a plank on your knees or toes. Rest whenever you need to.
Flexibility: sit with legs out straight and reach slowly toward your toes. Hold, breathe, no bouncing.

Right after the cardio station, count your pulse again and multiply by 4. How much higher is it?
Cool down with a slow walk. Which station felt hardest? Which part of fitness is that?

Safety: Stretch only until you feel a gentle pull, never pain. Stop and tell your grown-up if you feel dizzy or unwell.

Just for fun

Funny but true: when a blue whale dives deep, its huge heart can slow down to only about 2 beats per minute. Yours beats much faster, especially after skipping!

Your turn

What does bpm stand for?

You count 18 beats in 15 seconds. What is your heart rate in bpm?

Why do we multiply a 15-second count by 4?

Name the four parts of health-related fitness.

Name two benefits of doing cardio activities often.

Is holding a plank for 30 seconds mostly strength or endurance?

Do it and check: Find your resting heart rate.

More practice: warm-up

What is 25 × 4?

Which part of fitness does stretching build?

Will your heart rate be higher after sitting or after running?

Name one cardio activity you can do in winter.

True or false: being fit only means being able to run fast.

More practice: on your own

Owen's 15-second counts were 22 at rest and 37 after tag. What are his heart rates in bpm, and how much higher is the second one?

Mila can do 3 pull-ups. Tomas can hang from the monkey bars for 45 seconds. Which one shows more about muscular endurance? Explain.

Name an activity that builds two parts of fitness at once, and name the parts.

Why might a fit person's heart beat more slowly at rest?

Why is it better to count for 15 seconds right after you stop, instead of a full minute?

Challenge

Ana counted for 10 seconds instead of 15, and got 14 beats. What is her heart rate in bpm? Show your thinking.

Design a 4-station circuit for a friend, one station for each part of fitness. Name each station and the part it builds.

Ben's resting heart rate in September was 88 bpm. In December, after biking and swimming most weeks, it was 80 bpm. His friend says, "Your heart got weaker because it beats less!" Is that right? Explain.

Check your understanding

Quiz

You count 21 beats in 15 seconds. What is your heart rate?

Which is not one of the four parts of health-related fitness?

Holding a wall sit for 45 seconds mostly builds...

Which activity mainly builds cardiorespiratory endurance?

Why do we multiply a 15-second pulse count by 4?

What is one benefit of doing cardio activities often?

For parents and teachers

Big idea: In Grade 4, students build on Grade 3 heart-rate counting. They work out heart rate in beats per minute (15-second count × 4), compare resting and active heart rates, describe the benefits of cardiorespiratory activity, and learn the four parts of health-related fitness: cardiorespiratory endurance, muscular strength, muscular endurance and flexibility. This prepares them to set a fitness goal in the next lesson.

How to help at home:

Take heart rates together before and after an activity and compare. Your numbers will be different from your child's, and that's normal.
When you are active as a family, ask: "Which part of fitness did that build?"
Point out everyday strength and endurance (carrying groceries, shovelling, a long walk).

Common difficulties:

Multiplying by 4. Use doubling twice: 23 × 2 = 46, 46 × 2 = 92.
Strength vs endurance. Ask "How heavy?" (strength) or "How many times / how long?" (endurance).
Bouncing while stretching. Stretches should be slow and held, with a gentle pull and no pain.

Health note: The heart-rate numbers in this lesson are for learning, not medical checks. Children's heart rates vary a lot. If your child feels dizzy, has chest pain or unusual shortness of breath during activity, stop and talk to your doctor. A child with asthma should follow their asthma plan.

Math link: Multiplying by 4 and 6 and comparing with subtraction use Grade 4 math skills.

Social-emotional learning: Comparing data and choosing activities for each fitness part builds critical and creative thinking.