Student A spends 15 hours per day sitting in the classroom, library, student caf
ID: 2002089 • Letter: S
Question
Student A spends 15 hours per day sitting in the classroom, library, student cafeteria or dormitory. Another half-hour is spent walking between the dorm and lecture halls, and an hour is used for walking in the morning. Assume that laying down uses 5.0 kJ/min, sitting, 5.9 kJ/min, standing, 8.0 kJ/min, and walking, 13.4 kJ/min. Calculate student A’s daily energy requirement. Student B has the same routine as student A except that the hour of exercise is spent watching TV. Calculate the difference in energy requirements for these two students. Referring to the table attached, calculate the mass of fat, protein, or carbohydrate student A would have to ingest in order to satisfy their energy needs. How much glucose does student A need for daily exercise? List the underlying assumptions of your calculations.
Energy expenditure in a 70 kg human Form of Activity Total energy expenditure (kcal h^-1) lying still, awake 77 Sitting at rest 100 Typewritting rapidly 140 Dressing and Undressing 150 Walking on level, 2.6 mi/h 200 Sexual intercourse 280 Bicycling on level, 5.5 mi/h 304 Walking on 3 percent grade, 2.6 mi/h 357 Sawing wood or shoveling snow 480 Jogging, 5.3 mi/h 570 Rowing, 20 strokes/min 828 Maximal activity (untrained) 1440Explanation / Answer
Energy requirement for A = 15*60*5.9 +30*13.4 +1*13.4 + 7.5*60*5
= 5310 + 402 + 13.4 + 2250
= 7975.4 Kj/day
Energy requirement for B = 15*60*5.9 +30*13.4 +1*5.9 + 7.5*60*5
= 5310 + 402 + 5.9 + 2250
= 7967.9 Kj/day
Difference in energy requirements = 7.5 Kj/day
mass of fat = 15*100 +200*0.5 +1*357 +77*7.5/9
= 321.27 kg
mass of carbo hydrates = 2534.5/4
= 633.62 kg
mass of proteins =2534.5/4
= 633.62 kg
amount of glucose required = 570/4
= 142.5 kg