## Problem David B

David is a 70 kg student; as part of a research project he performed exercise on a treadmill. Table 10.8 shows his oxygen consumption and carbon dioxide production at different speeds.

### From these results and using information in Table 5.1, calculate:

• his energy expenditure at each speed of walking (in kJ/30 min);
• his PAR at each speed;

Table 10.8 Oxygen consumption and carbon dioxide production during 30 minutes of exercise on a treadmill at different speeds

Litres O,

kJ/30 min

Litres CO,

Per cent fat metabolized

### 1 km/h 158

1. 5 km/h 394
2. 5 km/h 525
3. 5 km/h 656
4. 5 km/h, incline + load 919

Table 10.9 Oxygen consumption and carbon dioxide production during 30 minutes exercise on a treadmill at 3.5 kmlh before and after breakfast

Litres Litres Per cent fat

O2 CO2 RQ metabolized

Fasting 394 285

### Fed 394 390

• his RQ (respiratory quotient, the ratio of CO2 produced/O2 consumed) at each speed;
• the percentage of fat and carbohydrate he is metabolizing at each speed (assuming that these are the only fuels he is utilizing).

Table 10.9 shows his oxygen consumption and carbon dioxide production walking on the treadmill at 3.5 km/h for 30 minutes early in the morning (after an overnight fast) and again 2 hours after eating breakfast.

What conclusions can you draw from these data?

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