Final answer:
Option (b) If ventilation is low, the respiratory rate will decrease while the volume of air per breath is increased. If ventilation is high, the respiratory rate will increase while the volume of air per breath decreases most accurately reflects ventilatory threshold one (VT1).
Step-by-step explanation:
Option (b) If ventilation is low, the respiratory rate will decrease while the volume of air per breath is increased. If ventilation is high, the respiratory rate will increase while the volume of air per breath decreases most accurately reflects ventilatory threshold one (VT1).
Ventilatory threshold one (VT1) is the point during exercise where there is an increased reliance on anaerobic metabolism and a subsequent increase in lactate production. At this point, the respiratory rate typically increases while the volume of air per breath decreases. As ventilation increases, the respiratory rate increases but the volume of air per breath decreases due to the demand for increased oxygen uptake.
For example, during moderate-intensity exercise, such as jogging, the individual may reach VT1, where they start to breathe more heavily and increase the frequency of breaths, but the depth of each breath decreases.