Question

The increase in ventilation during maximal exercise 

A. May exceed 100 litres/minute in a young 70 kg adult. 

B. Is smaller when the exercise is performed at high altitudes. 

C. Is related in part to a fall in pH due to lactic acidosis. 

D. Is related in part to stimulation of receptors in muscle (‘metaboreceptors’) by metabolic products of exercise. 

E. Does not involve the brain above the level of the brain stem (pons, midbrain and medulla).

Answer 1

A. True This is necessary to maintain a normal alveolar oxygen level and full blood oxygen saturation. 

B. False It is increased due to the low oxygen content at low atmospheric pressures; ventilatory ability can then be a limiting factor. 

C. True This occurs above the anaerobic/lactate threshold. 

D. True Ventilation is somewhat reduced if this input to the brain is blocked. 

E. False The precise matching of ventilation to exercise requirements is postulated to take place in an ‘exercise centre’ which receives an input from the cortical neurones initiating the exercise.