Question 19M.3.SL.TZ2.a
| Date | May 2019 | Marks available | [Maximum mark: 1] | Reference code | 19M.3.SL.TZ2.a |
| Level | SL | Paper | 3 | Time zone | TZ2 |
| Command term | State | Question number | a | Adapted from | N/A |
A study was conducted on 25 healthy, non-smoking males to look at the effect of exercise and altitude on ventilation rate. Subjects were first asked to rest in a sitting position for six minutes. They then pedalled for three periods of six minutes at increasing exercise intensity: at 20 %, 30 % and 40 % of their maximal aerobic power. The entire study was conducted either in normal sea level oxygen conditions or in lower oxygen conditions simulating an altitude of 4000 m. The results are shown in the bar chart.
[Source: E Hermand, et al., (2015), Periodic breathing in healthy humans at exercise in hypoxia,
Journal of Applied Physiology, 118, pages 115–123. https://doi.org/10.1152/japplphysiol.00832.2014]
State one other variable that should have been controlled in this study.
[1]
age/height/fitness level/weight/room temperature/rest in between tests/model or type of bike ✔
Other valid factor. Only mark first factor listed.
Do not accept sex, health, smoking, oxygen level or altitude as this already listed.
In this question the candidates were asked to look at data on the effect of exercise and altitude on ventilation rate. Most candidates could state one other variable that should have been controlled in this study.
