Date | November 2020 | Marks available | 3 | Reference code | 20N.3.HL:.tz0.3 |
Level | Higher Level | Paper | Paper 3 | Time zone | time zone 0 |
Command term | Discuss | 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.
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.
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.
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;
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.
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;
Examiners report
Overall, answered well. In general, it lacked technical language.
Varied answers here, conflicting answers.
Answered poorly, not many answered with AMS/HAPE or HACE.