Lesson overview
Exercise and heart health: What happens to your heart rate when you exercise?
Count a volunteer’s pulse at the wrist, listen to the valves with a stethoscope and read an ECG strip, then run a step test: decide how long to count, and watch the heart rate rise, level off and fall back to resting. Look into a working muscle to explain why the heart beats faster, compare the same test after eight weeks of training, and learn how coronary heart disease starts and what diet and exercise can do.
Suggested sequence
- Lesson 1 · Watching the heart. Watching the heart: the ECG, the pulse rate and the sounds of the valves closing; a resting heart rate from a count. Read together (10–15 min), show or explore the experiment (10 min), practise with self-checking (15–20 min).
- Lesson 2 · Exercise and the heart rate. Exercise and the heart rate: a step test, the rise, the level and the recovery time; how long to count; (Supplement) why the heart beats faster; after eight weeks of training. Read together (10–15 min), show or explore the experiment (10 min), practise with self-checking (15–20 min).
- Lesson 3 · Coronary heart disease. Coronary heart disease: blocked coronary arteries, the risk factors, and the roles of diet and exercise. Read together and discuss (15–20 min), practise with self-checking (20–25 min).
- End of module · final check. 6 new questions, 20–30 min, without hints or notes; pupils check their answers once they have answered them all.
- One to two weeks later · return questions. 9 questions, 15 min, lesson closed.
Learning goals
Part 1: Watching the heart
- State three ways of monitoring the activity of the heart: ECG, pulse rate, sounds of the valves closing (9.2.3)
- Work out a heart rate in beats per minute from a pulse count (9.2.4)
- Work out a heart rate from an ECG trace or the heart sounds (9.2.3)
Part 2: Exercise and the heart rate
- Describe the effect of physical activity on the heart rate (9.2.4)
- Plan and evaluate a fair investigation of physical activity and the heart rate (9.2.4)
- Supplement: explain the effect of physical activity on the heart rate (S9.2.11)
Part 3: Coronary heart disease
- Describe coronary heart disease in terms of the blockage of coronary arteries (9.2.5)
- State the possible risk factors for coronary heart disease (9.2.5)
- Discuss the roles of diet and exercise in reducing the risk of coronary heart disease (9.2.6)
Misconceptions to listen for
- “an ECG, the pulse rate and listening to the heart muscle contracting” — The muscle contracting makes almost no sound you can hear. The lub and the dub are valves closing.
- “an ECG, the breathing rate and listening to the valves closing” — The breathing rate is the activity of the lungs. The heart is counted at the pulse.
- “the blood pressure, the pulse rate and listening to the valves opening” — Valves make their sound as they close, not as they open, and blood pressure is not one of the three ways.
- “20 ÷ 4 = 5 beats per minute.” — A minute is longer than 15 seconds, so more beats happen in it: multiply by 4.
- “20 × 15 = 300 beats per minute.” — Multiply by the number of 15-second lots in a minute, which is 4, not by 15.
- “3.5 ÷ 5 = 0.7 s between spikes.” — Five spikes have four gaps between them, and the first spike is at 0.3 s, not at 0. Subtract one spike's time from the next.
- “0.8 × 60 = 48 beats per minute.” — Divide the minute by the time of one beat: 60 ÷ 0.8.
- “The stethoscope picks up the heart muscle contracting.” — The muscle makes almost no sound you can hear. The lub and dub are the valves closing.
- “The pulse is the heart beating in the wrist.” — The heart stays in the chest; the pulse is the artery wall stretched by a surge of blood.
- “The pulse picks up the oxygen carried in the blood.” — Feeling a pulse tells you nothing about oxygen. You feel the artery wall stretch once at each beat.
Scope
Monitoring the heart by ECG, pulse rate and the sounds of valves closing (9.2.3); the effect of physical activity on the heart rate, investigated with a step test (9.2.4); coronary heart disease as the blockage of coronary arteries, and its possible risk factors (9.2.5); the roles of diet and exercise in reducing the risk (9.2.6); and, in the Supplement, why physical activity raises the heart rate (9.2.11). The structure of the heart and its valves is in The heart and double circulation; anaerobic respiration and the oxygen debt are in the respiration module.