Question

A 45-year-old female has a predicted O2 of 2.8 L. She does not have any identified abnormalities other than being short of breath with exercise. What would be the most appropriate cycle incremental or ramp protocol to use for her study?

Answer 1

To calculate the efficiency of a subject on a treadmill who puts out 100 W of work and consumes 2.00 L/min of oxygen, we relate the power output to the energy input. Assuming 1 L of oxygen equals 20.9 kJ, the subject's efficiency is approximately 14.3%.

Step-by-step explanation:

The question is asking for the efficiency of a subject on a treadmill who is producing 100 W of power while consuming oxygen at a rate of 2.00 L/min. To calculate efficiency, we need to relate the power output to the energy input from the oxygen. The energy content of oxygen can be found from the standard metabolic equivalent tables (such as in Table 7.5 hinted in the question). Let's presume the given Table 7.5 shows that the consumption of 1.00 L of oxygen corresponds to 20.9 kJ of energy (a standard number). To find the efficiency, we follow these steps:

1. Calculate the total energy input from the oxygen consumed per minute. As 1 L of oxygen is 20.9 kJ, the energy input for 2.00 L/min would be 2.00 L/min × 20.9 kJ/L = 41.8 kJ/min.
2. Convert the energy input per minute to watts (1 W = 1 J/s). Since 1 kJ = 1000 J and 1 min = 60 s, 41.8 kJ/min equals to 41.8 × 1000 J/min / 60 s/min = 697 W.
3. Now, we can calculate efficiency by dividing the power output by the power input and multiplying by 100 to get a percentage. Thus, Efficiency = (100 W / 697 W) × 100 = approx. 14.3%.

Therefore, the efficiency of the subject on the treadmill is approximately 14.3%.