| Date | May 2019 | Marks available | 3 | Reference code | 19M.2.HL:.tz0.7 |
| Level | Higher Level | Paper | Paper 2 | Time zone | time zone 0 |
| Command term | Explain | Question number | 7 | Adapted from | N/A |
Question
The heart rate data is from a study of younger swimmers (aged 14–16 years) and older swimmers (aged 35–40 years) during a 1500 m swim.
Explain the lower increase of heart rate in older swimmers.
Markscheme
maximum heart rate decreases with age ✔
therefore, upon exercise, older swimmers are closer to their maximal heart rate ✔
depresses the spontaneous electrical activity of the sinoatrial node ✔
the heart becomes less sensitive to adrenaline/epinephrine with age ✔
[3 max]
Examiners report
This was the most challenging question of the paper. Most students who did answer this question partially earned a mark for the recognition that maximum heart rate decreases with age.
Syllabus sections
- 22M.1.SL.tz0.8: Which describes the cardiac output of an athlete recovering from strenuous exercise?
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18N.2.SL.tz0.2e:
Distinguish how cardiac output, stroke volume and resting heart rate would differ between trained and untrained women during exercise.
- 18N.2.HL:.tz0.9b: Distinguish how cardiac output, stroke volume and resting heart rate would differ between...
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21N.1.SL.tz0.8:
What changes occur to a boxer’s stroke volume and heart rate while punching during a bout?
