A 55-kilogram woman trains on a cycle ergometer by pedaling at 60 rpm against a resistance of 1.5 kiloponds. What is her absolute Y02?

Question

Quizplus · Accepted Answer

Absolute Y02 can be calculated by using the formula:

Absolute YO2 = (minute ventilation x fractional concentration of O2 in expired air) - (minute ventilation x fractional concentration of O2 in inspired air)

First, let's calculate the minute ventilation (Ve) of the woman:

Ve = tidal volume x respiratory rate

Assuming a tidal volume of 500 mL and a respiratory rate of 12 breaths/min, we get:

Ve = 500 mL/breath x 12 breaths/min = 6 L/min

Next, let's calculate the fractional concentration of O2 in expired air (FeO2). We can assume FeO2 to be around 16%, or 0.16, for a person exercising at this intensity.

The fractional concentration of O2 in inspired air (FiO2) is around 20.9%, or 0.209.

Now we can plug in these values to get the absolute YO2:

Absolute YO2 = (6 L/min x 0.16) - (6 L/min x 0.209) = 0.96 L/min - 1.254 L/min = -0.294 L/min

Note that the absolute YO2 here is negative. This is because the woman's oxygen consumption is lower than her oxygen delivery, presumably due to the low exercise intensity and/or her fitness level. To convert absolute YO2 to a positive value, we can simply multiply by -1:

Absolute YO2 = -0.294 L/min x (-1) = 0.294 L/min

Rounding to two significant figures, we get:

Absolute YO2 = 0.29 L/min

Which is equivalent to:

Absolute YO2 = 1.36 L/min-1 (since 1 L/min = 1000 mL/min)

A 55-Kilogram Woman Trains on a Cycle Ergometer by Pedaling