A 16-year-old student whose heart rate is 140 beats per minute would be considered to be in which of the following exercise states?

The choice indicating that the student is performing sub-maximal exercise is the most accurate based on the information provided. Sub-maximal exercise refers to activity that is below a person's maximum capacity, meaning the individual is exercising at an intensity that does not reach their maximum heart rate. For a 16-year-old, a heart rate of 140 beats per minute is generally considered to fall within a moderate range of intensity, which does not approach the upper limits of heart rate typically observed during maximal exercise.

Maximal exercise would typically involve pushing the heart rate to near maximum levels, often above 85% of the individual's maximum heart rate. For a 16-year-old, the estimated maximum heart rate can be approximated by subtracting their age from 220, which would give a maximum around 204 beats per minute. Thus, 140 beats per minute is clearly below the threshold where maximal effort is occurring.

While being at the ventilatory threshold involves a point during progressive exercise where ventilation starts to increase disproportionately to oxygen uptake, it is unlikely that a heart rate of 140 indicates a transition to this state, as this heart rate often corresponds to steady-state exercise below the ventilatory threshold. Hyperventilation refers to a condition where breathing becomes rapid and shallow