Ashley is a 130 lb athlete who biked on a cycle ergometer at a steady state of exercise for 48 minutes. Her average VO2 was 2.72 LO2/min. and her average VCO2 was 2.24 LCO2/min. What was her total energy expenditure (in kcals) during the entire bout of exercise? Round to the nearest whole number. A. 712 kcals
B. 687 kcals
C. 603 kcals
D. 630 kcals

correct option is D. 630 kcals

Step-by-step explanation:

given data

Ashley weight =  130 lb

exercise time = 48 minutes

VO2 = 2.72 LO2/min

VCO2 = 2.24 LCO2/min

to find out

total energy expenditure

solution

first we get here respiratory exchange ratio that is

respiratory exchange ratio (RER) =   ...........1

RER =  

RER =  0.823

now we get here calorific value that is

calorific value = 3.815 + 1.23 × RER

calorific value =  3.815 + 1.23 × 0.823

calorific value = 4.827 kcal/L O2

so now we get energy expended that is

energy expended = VO2 × calorific value × time

energy expended = 2.72 × 4.827  × 48

energy expended = 630 kcals

so correct option is D. 630 kcals

the answer is 99.