Question

1. Participants did the VO2 max test in running machine. Define RER and give the equation for RER. What type of substrate/fuel was the subject utilizing the most at baseline? What type of substrate/fuel was the subject utilizing the most at his/her O2max? What was the trend for RER from rest to O2max and why did this trend occur in physiological terms?

2.Do you think the subject’s O_2max would be higher or lower if the submaximal test was performed on a treadmill? Give the physiological reasoning for your answer.

Answer 1

1)

— RER - respiratory exchange ratio

It is ised to determine the fuel usage during exercise.

R = V CO2÷V O2

or amount of CO2 produced ÷amount of O2 consumed

— at baseline (low intensity exercise)the fuel used mostly ìs fat.

— at MAX V O2 (high intensity excercise) the fuel utilised is carbohydrate.

( Maximum V O2 is the highest rate of oxygen consumption by a person during exercise. )

— trend for RER from rest to O2 max - it changes from 0.7 to 1.0

Physiological basis for this trend (rest to exercise) :

ONSET OF EXERCISE: ATP requirement is met through ANAEROBIC SYSTEMS (fat metabolism)

AS INTENSITY INCREASES:

- ATP production increases immediately

-oxygen uptake increases rapidly and reaches steady state within 4 minutes.

- after steady state is reached, ATP requirement is met through aerobic ATP production ( aerobic glycolysis, krebs cycle)

2) i think the V O2 max would be higher in the subject if the submaximal test is performed on treadmill

Because :

When there is increased muscle mass put at the task there is higher VO2 max due to more cellular utilization of oxygen.

Treadmill basically activates or stimulates all the muscles leading to increased oxygen consumption

Submaximal running exercise induces a higher oxygen uptake and energy expenditure