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Information can be presented in graphical form. You will need to know how to work out what this information is telling you and answer questions related to the information presented.

Below is a graph showing the heart rates of a fit person and unfit person exercising at the same intensity for 15 minutes.

This graph shows a number of things:

1. when a person exercises their heart rate increases
2. when a person stops exercising their heart rate decreases
3. an unfit person has a higher resting heart rate than a fit person
4. an unfit person has a higher heart rate when they are exercising at the same intensity
5. a fit person takes less time for their heart rate to return to resting values after taking part in exercise

Example question:

Explain the difference in time that it takes for a fit person's heart rate to return to resting levels compared to an unfit person's heart rate. (4)

It takes less time for a fit person's heart rate to return to resting levels compared to an unfit person's heart rate. (1) This is because the fit person's heart is able to pump out more blood each time it contracts (1) because of cardiac hypertrophy (1). This means that the oxygen debt (1) is re-paid at a faster rate in the fit person so their heart rate can return to resting levels more quickly compared to an unfit person. (1)

You may be asked questions related specifically to interpreting the information on the graph, eg What happens to heart rate when a person takes part in exercise?

Or you may be asked physiological questions about how adaption of the cardiovascular system means there is a difference between heart rate of a fit and unfit person.

Here's an example:

The green curve shows a lower exercising heart rate than that of the purple curve. Evaluate the physiological differences between the two performers that produce this difference.

The answer would include differences such as:

• the fit athlete has lower resting heart rate than the unfit athlete
• the fit athlete has greater stroke volume than the unfit athlete
• the fit athlete has greater heart rate range than the unfit athlete
• the fit athlete has greater potential cardiac output than the unfit athlete
• the fit athlete can work at higher intensities aerobically
• the fit athlete has larger/thicker heart wall than the unfit athlete
• the fit athlete has a faster recovery than the unfit athlete and will be ready to train/perform again sooner
• the fit athlete removes lactic acid more efficiently than the unfit athlete