The Pulse Rate Today we will learn: What our heart rate can tell us how to take our pulse rate how to record results

The Heart Every organ and muscle in our body requires oxygen to work. Oxygen enters our body through our lungs when we breathe in. Oxygen is then carried to our organs by tiny red blood cells in our blood. The heart is a powerful muscle which pumps blood around our body, delivering oxygen to each organ.

The Pulse The pulse tells us how many times our heart is beating per minute. It is measured in “beats per minute”, or BPM. It is your blood “pulsing” through the blood vessels close to the surface of your skin as it is pushed around the body by the heart. A child's pulse rate is normally between around 80 BPM.

What can the pulse tell us? How hard our heart is working How healthy and fit we are Q: How do you think our heart rate can tell us this?

Our experiment…. We are going to investigate the effect of rest and exercise on our pulse rate. This will tell us how hard our heart is working during rest and exercise. We will: Record the pulse rate during rest Run on the spot for 60 seconds Record our pulse rate after exercise Compare the differences between pulse rate during rest and exercise

How do we take our pulse? Our pulse can be felt under the skin either at the base of the neck, or the inside of the wrist. Can you feel yours?

Things to consider In science, it’s very important that we start with a prediction of how we think the experiment will go. It is also very important that results are reliable. Because of this, we will record pulse three times before and after exercise. Results should also be correctly recorded. Because of this, we are going to fill-in a sheet during the experiment. This will help us know: If our prediction was correct. That our results are reliable. We won’t forget our results before we get a chance to compare them at the end of our experiment.

Experiment part 1: Nominate one person in your group to be your test subject (volunteer who will have their pulse rate recorded). Make your prediction – do you think pulse rate will go up, down or stay the same after exercise? Record the number of pulses you can feel in 30 seconds…

30 Second Timer 9 8 10 12 13 7 11 6 1 End 2 3 5 4 14 16 26 25 27 28 30 29 24 23 18 17 19 20 22 21 15

30 Second Timer 9 8 10 12 13 7 11 6 1 End 2 3 5 4 14 16 26 25 27 28 30 29 24 23 18 17 19 20 22 21 15

30 Second Timer 9 8 10 12 13 7 11 6 1 End 2 3 5 4 14 16 26 25 27 28 30 29 24 23 18 17 19 20 22 21 15

Experiment part 2: Run on the spot for 60 seconds…

60 Second Timer End 1 minute This ‘sand timer’ will start on a mouse click anywhere on the slide. The ‘sand’ will drain from the top section to the lower section and when completed will show the word ‘End’. To change the timings of this timer, you need to enter the animation settings, and change the timings for the Isosceles Triangles. There will be 2 that need changing (to the same amount) – one animates the top triangle emptying, whilst the other animates the bottom triangle filling. When you change the timings these have to entered as a number of seconds. End

60 Second Timer End 1 minute This ‘sand timer’ will start on a mouse click anywhere on the slide. The ‘sand’ will drain from the top section to the lower section and when completed will show the word ‘End’. To change the timings of this timer, you need to enter the animation settings, and change the timings for the Isosceles Triangles. There will be 2 that need changing (to the same amount) – one animates the top triangle emptying, whilst the other animates the bottom triangle filling. When you change the timings these have to entered as a number of seconds. End

60 Second Timer End 1 minute This ‘sand timer’ will start on a mouse click anywhere on the slide. The ‘sand’ will drain from the top section to the lower section and when completed will show the word ‘End’. To change the timings of this timer, you need to enter the animation settings, and change the timings for the Isosceles Triangles. There will be 2 that need changing (to the same amount) – one animates the top triangle emptying, whilst the other animates the bottom triangle filling. When you change the timings these have to entered as a number of seconds. End

Our Results… Were there any changes in pulse rate before and after exercise? If there were, what changes did you see? Why do you think you saw these changes? What do you think this tells us about the role of the heart during exercise?

Scientist’s Results… This experiment was what scientists used in early studies investigating the effect of exercise on the heart, using the exact same equipment that we have just used! These experiments found that heart rate (pulse) increases with exercise, as the heart has to work harder to deliver oxygen to our muscles and organs that are working more to power us faster!