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How do you work out maximum heart rate and the aerobic and anaerobic training zones?

Maximum heart rate and the calculation of aerobic and anaerobic training zones, and the link between training intensity and aerobic or anaerobic exercise.

A focused answer to the WJEC GCSE PE topic on training zones and heart rate, covering how to estimate maximum heart rate, how to calculate the aerobic and anaerobic training zones as percentages, and how training intensity decides whether exercise is aerobic or anaerobic.

Generated by Claude Opus 4.89 min answer

Reviewed by: AI editorial process; not yet individually human-reviewed

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  1. What this dot point is asking
  2. Maximum heart rate
  3. The training zones
  4. Calculating a training zone
  5. Intensity and the energy systems
  6. Measuring heart rate during training
  7. Why this matters

What this dot point is asking

WJEC wants you to estimate maximum heart rate, calculate the aerobic and anaerobic training zones, and link training intensity to whether exercise is aerobic or anaerobic.

Maximum heart rate

MHR=220age (in years)\text{MHR} = 220 - \text{age (in years)}

For example, a 16-year-old has an estimated maximum heart rate of 22016=204220 - 16 = 204 beats per minute (bpm). It falls as you get older.

The training zones

To train a particular energy system, a performer keeps their heart rate within a target zone, given as a percentage of maximum heart rate.

  • Aerobic training zone: about 60 to 80% of MHR. Exercise here uses oxygen to release energy and can be kept up for a long time. It develops cardiovascular endurance. Continuous and fartlek training work in this zone.
  • Anaerobic training zone: about 80 to 90% of MHR. Exercise here is too intense to be fuelled by oxygen alone, so energy is released without oxygen and lactic acid builds up. It can only be sustained for short bursts and develops speed and power. Sprint interval training works in this zone.

Calculating a training zone

To find the limits of a zone:

  1. work out maximum heart rate (220 minus age),
  2. multiply by the lower percentage for the bottom of the zone,
  3. multiply by the higher percentage for the top of the zone.

Intensity and the energy systems

The intensity of exercise decides whether it is aerobic or anaerobic.

  • Lower intensity, longer duration (in the aerobic zone): the body has time to use oxygen, so it works aerobically.
  • Higher intensity, shorter duration (in the anaerobic zone): oxygen cannot be supplied fast enough, so the body works anaerobically and lactic acid builds up, causing fatigue.

This is why a marathon is aerobic and a 100 m sprint is anaerobic.

Measuring heart rate during training

To check they are in the right zone, a performer measures their heart rate. This can be done by:

  • counting the pulse at the wrist (radial) or neck (carotid) for 15 seconds and multiplying by four to get beats per minute, or
  • using a heart rate monitor (a chest strap or watch), which gives a continuous, more accurate reading.

A performer takes their resting heart rate before exercise, their working heart rate during it, and watches how quickly the heart rate falls afterwards. A faster recovery rate (the heart rate dropping back towards resting quickly) is a sign of better aerobic fitness.

Why this matters

Setting the right training zone is how the principles of training (especially intensity in FITT) are put into practice, and it decides which methods of training suit a performer. The link between intensity and the aerobic or anaerobic systems carries straight into the exercise physiology topic on energy systems.

Exam-style practice questions

Practice questions written in the style of WJEC exam questions on this dot point, with worked answer explainers. The year tag is the paper they imitate, not the source.

WJEC style3 marksCalculate the maximum heart rate of a 15-year-old and work out the lower and upper limits of their aerobic training zone (60 to 80% of maximum).
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A 3-mark calculation: one mark for the maximum heart rate and one for each limit.

Maximum heart rate is estimated as 220 minus age, so 220 minus 15 equals 205 beats per minute. The aerobic zone runs from 60% to 80% of this. The lower limit is 60% of 205, which is 0.6 times 205 equals 123 beats per minute. The upper limit is 80% of 205, which is 0.8 times 205 equals 164 beats per minute.

So the aerobic training zone for a 15-year-old is roughly 123 to 164 beats per minute. Reward the correct method even if rounding differs slightly.

WJEC style4 marksExplain the difference between the aerobic and anaerobic training zones and give an activity that would be carried out in each.
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A 4-mark question: two marks for the difference and two for suitable activities.

The aerobic training zone is roughly 60 to 80% of maximum heart rate; exercise here uses oxygen to release energy and can be sustained for a long time. An example is a steady 40-minute run. The anaerobic training zone is roughly 80 to 90% of maximum heart rate; exercise here is too intense to be fuelled fully by oxygen, so energy is released without oxygen and lactic acid builds up, so it can only be sustained for short bursts. An example is a series of 200 m sprints.

Markers reward the percentage ranges, the use or non-use of oxygen, the build-up of lactic acid anaerobically, and a sensible activity for each zone.

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