Question

In detail, Explain the physiological basis behind VO2 plateaus, Peak RER > 1.1, peak blood lactate level > 8.0 mM, and a peak heart rate no less than 10 bpm below age predicted max heart rate in terms of maximal VO2 (max oxygen consumption).

Answer 1

These are 4 separate questions and I will help with maximum possible questions with the limited time available.

The VO2 graph plateaus after it reaches VO2 max. This is because the cardio-respiatory system reached its maximum physiological function. That means heart has reached peak function which is 4-5 times of its resting cardiac output . Further more increase in exercise intensity cannot increase VO2.

RER is the ratio of amount of CO2 produced during metabolism and amount of O2 utilised. RER peak is > 1.1 because more CO2 is produced than O2 used. During exercise the main fuel is carbohydrates and RQ value of carbohydrates is 1. At the peak of the exercise, more CO2 is produced than the O2 used because at VO2 max, no more extra O2 can be utilised, but extra CO2 can be produced.