Year 6 Science: Pulse and heart rate
Part of the Year 6 Science the circulatory system and transport chapter. Chapter overview · whole chapter on one page
Pulse and heart rate
The pulse is the beat you can feel in an artery, caused by the heart pushing blood out. The heart rate is the number of beats per minute.
To measure the pulse, count the beats for 15 seconds, then multiply the count by 4 to get beats per minute. The pupils did this three times each, and took the mean.
During exercise, the muscles need more oxygen and nutrients. The heart beats faster, so the blood carries more oxygen to the body.
The table gives the 15-second counts for each pupil, and the rate per minute.
| Pupil | Rest: beats in 15 s | Rest (per minute) | After exercise: beats in 15 s | After exercise (per minute) |
|---|---|---|---|---|
| Ali | 18 | 72 | 25 | 100 |
| Priya | 16 | 64 | 23 | 92 |
| Mo | 20 | 80 | 27 | 108 |
| Mean | 72 | 100 |
Key ideas
- Pulse rate = the beats counted in 15 seconds, multiplied by 4.
- The heart beats faster during exercise, to carry more oxygen to the muscles.
- Repeat a count, and find the mean, to make a result more reliable.
- Compare rest and exercise with the same method each time.
Method. Multiply the 15-second count by 4.
- Read the count. Ali counted 18 beats in 15 seconds.18
- Multiply. Multiply 18 by 4 to get beats per minute.18 x 4 = 72
- Write the answer. 72 beats per minute
Check. The table gives 72 for Ali at rest. ✓
Watch out. Do not forget to multiply by 4 when you use 15 seconds.
Method. Subtract the rest mean from the exercise mean.
- Read the two means. The rest mean is 72, and the exercise mean is 100.72 and 100
- Subtract. The rise is 100 minus 72.100 - 72 = 28
- Write the answer. 28
Check. 72 + 28 = 100. ✓
Method. Multiply the count by 4.
- Read the count. The count was 27 beats in 15 seconds.27
- Multiply. So the rate is 27 x 4.27 x 4 = 108
- Write the answer. 108
Check. The table gives 108 for Mo after exercise. ✓
Watch out
Watch out: a 15-second count must be multiplied by 4. If you forget, the answer is four times too small.
Exam tip
Exam tip. When you compare rest and exercise, use the same method both times, and say how many repeats you made.
Try it (with your teacher, or a grown-up at home). With a grown-up, count your pulse for 15 seconds at rest, and multiply by 4. Then march on the spot for one minute, sit down, and count again. Stop if you feel dizzy or unwell. Repeat each count three times, and find the mean. Write both results in a table.
Exercise 3E Pulse and heart rate
Method. Read the table.
- Find Ali. Ali is the first row of the table.Ali
- Read the count. His count at rest is 18 beats in 15 seconds.18
- Write the answer. 18
Check. 18 x 4 = 72. ✓
Method. Read the table.
- Find Priya. Priya is the second row of the table.Priya
- Read the rate. Her rate after exercise is 92 beats per minute.92
- Write the answer. 92
Check. Her count was 23 in 15 seconds, and 23 x 4 = 92. ✓
Method. Read the table.
- Find Mo. Mo is the third row of the table.Mo
- Read the count. His count at rest is 20 beats in 15 seconds.20
- Write the answer. 20
Check. 20 x 4 = 80, which is his rate per minute. ✓
Method. Read the mean row of the table.
- Read the row. The mean row gives the rest rate as 72.72
- Write the answer. So the mean resting rate is 72 beats per minute.72
- Write the answer. 72
Check. The rates are 72, 64 and 80, with a mean of 72. ✓
Method. Read the mean row of the table.
- Read the row. The mean row gives the rate after exercise as 100.100
- Write the answer. So the mean after exercise is 100 beats per minute.100
- Write the answer. 100
Check. The rates are 100, 92 and 108, with a mean of 100. ✓
Method. Compare the rates after exercise.
- Read the rates. The rates after exercise are 100, 92 and 108.108
- Pick the highest. Mo had the highest rate, at 108 beats per minute.Mo
- Write the answer. Mo
Check. Mo's rate after exercise was 108. ✓
Method. Compare the resting rates.
- Read the rates. The resting rates are 72, 64 and 80.64
- Pick the lowest. Priya had the lowest resting rate, at 64 beats per minute.Priya
- Write the answer. Priya
Check. Priya counted 16 beats in 15 seconds. ✓
Method. Subtract the mean at rest from the mean after exercise.
- Read the means. The mean at rest is 72, and after exercise it is 100.72 and 100
- Subtract. The rise is 100 minus 72.100 - 72 = 28
- Write the answer. 28
Check. 72 + 28 = 100. ✓
Method. Multiply the count by 4.
- Read the count. The count is 25 beats in 15 seconds.25
- Multiply. Multiply 25 by 4 to get beats per minute.25 x 4 = 100
- Write the answer. 100
Check. Half of 100 is 50, which is the count in 30 seconds. ✓
Method. Divide the rate by 4.
- Read the rate. Mo's rate at rest is 80 beats per minute.80
- Divide. The count in 15 seconds is 80 divided by 4.80 divided by 4 = 20
- Write the answer. 20
Check. The count multiplied by 4 gives 80 again. ✓
Method. Think about what the muscles need.
- Think about the muscles. Muscles work harder during exercise, and use more oxygen.more oxygen
- Think about the heart. The heart pumps faster to deliver more oxygen and nutrients in the blood.pumps faster
- Write the answer. Accept any sentence that says the muscles need more oxygen and nutrients, so the heart pumps faster to deliver them.
Check. A faster heart rate delivers more blood each minute. ✓
Method. Check the time.
- Think about the time. There are four lots of 15 seconds in one minute.4 x 15 = 60
- Decide. So multiplying by 4 gives beats per minute, and the answer is yes.yes
- Write the answer. yes
Check. Four 15-second periods make 60 seconds. ✓
Method. Think about repeats.
- Think about one count. One count can be affected by chance, such as losing count.chance
- Think about the mean. The mean of three counts evens out these errors.evens out
- Write the answer. Accept any sentence that says the mean of three counts evens out chance errors, so the result is more reliable than one count.
Check. Repeats are a method of working scientifically. ✓