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Date November 2020 Marks available 2 Reference code 20N.3.HL:.tz0.3
Level Higher Level Paper Paper 3 Time zone time zone 0
Command term Identify Question number 3 Adapted from N/A

Question

Identify two physiological responses to hypoxia for a cyclist immediately after arriving at a training camp at 2000 m altitude.

[2]
a.

The cyclist remains at the training camp for a month. Explain the physiological changes resulting from hypoxia that will improve their performance at sea level.

[4]
b.

Mountain stages of an endurance cycle race take place between 2000 and 2500 m above sea level. Discuss the effects of altitude on the cyclist and their performance.

[3]
c.

Markscheme

hyperventilation;

elevated submaximal heart rate;

limited glycolysis functioning;

reduced saturation of hemoglobin;

blood / stroke volume reduction;

there is an increase in urine production at altitude / diuresis;

a.

Blood adaptations:
decreased plasma volume, associated with drier air / fluid loss;

increased hemoglobin concentration, associated with more EPO;

increased total number of RBC, associated with renal / kidney release of more EPO;

Muscle adaptations:
reduced lean muscle body mass;

increased capillary density / volume in muscles;

increased mitochondrial density;

Cardiorespiratory adaptations:
increase in pulmonary ventilation / increase VO2max;

improved cardiac output;

increased capillary density in the lungs;

Award [2] max per adaptation.

b.

lower air density results in lower drag, therefore faster travel;

lower partial pressure results in reduced oxygen uptake, therefore maximum aerobic capacity;

altitude can cause AMS / HAPE / HACE & results in a drop in performance;

altitude can cause a loss of fluid & results in dehydration / drop in performance;

less air resistance/lower air density;

gravity is reduced very slightly which may further improve performance;

c.

Examiners report

Overall, answered well. In general, it lacked technical language.

a.

Varied answers here, conflicting answers.

b.

Answered poorly, not many answered with AMS/HAPE or HACE.

c.

Syllabus sections

Option A: Optimizing physiological performance » A.5. Training and performance at altitude (HL only) » A.5.3. Outline the physiological effects of altitude.
Option A: Optimizing physiological performance » A.5. Training and performance at altitude (HL only)
Option A: Optimizing physiological performance

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