Exercise is associated with alterations to many basic physiological processes, including changes in metabolism and the cardiovascular system. As the intensity of exercise rises, both the cardiac output and oxygen consumption increase, as shown in Figure 1.Figure 1 Changes in cardiac output and oxygen consumption in response to various levels of exerciseThe cardiac output CO represents the volume of blood pumped by the heart in 1 minute. The CO is calculated from the heart rate HR and stroke volume SV using the equationCO = HR ∙ SVEquation 1Experimental data has shown that the HR increases linearly with the exercise output Eout, leading to the relationshipHR = 0.65 ∙ Eout + 75Equation 2The metabolism of nutrients consumes oxygen and generates carbon dioxide as a waste product. The amount of carbon dioxide generated depends on the type of macronutrient that is consumed. For example, when carbohydrates are metabolized, every liter of oxygen consumed causes the generation of 1.0 liter of carbon dioxide. Alternatively, the metabolism of fats leads to 0.7 liters of carbon dioxide per liter of oxygen, and the metabolism of proteins generates 0.8 liters of carbon dioxide for each liter of oxygen. Question 56While exercising on a treadmill, a person has a cardiac output of 15 L/min and produces carbon dioxide at 0.091 mol/min. What is their ratio of metabolizing carbohydrates to fats during the exercise? (Assume all gasses are ideal and are at STP.)A.1:2B.1:1C.1:0D.2:1Submit
Question
Exercise is associated with alterations to many basic physiological processes, including changes in metabolism and the cardiovascular system. As the intensity of exercise rises, both the cardiac output and oxygen consumption increase, as shown in Figure 1.Figure 1 Changes in cardiac output and oxygen consumption in response to various levels of exerciseThe cardiac output CO represents the volume of blood pumped by the heart in 1 minute. The CO is calculated from the heart rate HR and stroke volume SV using the equationCO = HR ∙ SVEquation 1Experimental data has shown that the HR increases linearly with the exercise output Eout, leading to the relationshipHR = 0.65 ∙ Eout + 75Equation 2The metabolism of nutrients consumes oxygen and generates carbon dioxide as a waste product. The amount of carbon dioxide generated depends on the type of macronutrient that is consumed. For example, when carbohydrates are metabolized, every liter of oxygen consumed causes the generation of 1.0 liter of carbon dioxide. Alternatively, the metabolism of fats leads to 0.7 liters of carbon dioxide per liter of oxygen, and the metabolism of proteins generates 0.8 liters of carbon dioxide for each liter of oxygen. Question 56While exercising on a treadmill, a person has a cardiac output of 15 L/min and produces carbon dioxide at 0.091 mol/min. What is their ratio of metabolizing carbohydrates to fats during the exercise? (Assume all gasses are ideal and are at STP.)A.1:2B.1:1C.1:0D.2:1Submit
Solution
To solve this problem, we first need to understand that the volume of CO2 produced is directly related to the type of macronutrient being metabolized.
Given that the person is producing 0.091 mol/min of CO2, we need to convert this to liters. At STP (Standard Temperature and Pressure), 1 mol of an ideal gas occupies 22.4 L. Therefore, the volume of CO2 produced is 0.091 mol/min * 22.4 L/mol = 2.04 L/min.
We know that the metabolism of carbohydrates generates 1.0 L of CO2 per L of O2, and the metabolism of fats generates 0.7 L of CO2 per L of O2. Let's denote the volume of O2 used for carbohydrate metabolism as Vc and for fat metabolism as Vf.
We can set up the following equations based on the information given:
Vc + Vf = 15 L/min (total cardiac output) 1.0 * Vc + 0.7 * Vf = 2.04 L/min (total CO2 production)
Solving this system of equations, we get Vc = 0.84 L/min and Vf = 14.16 L/min.
Therefore, the ratio of metabolizing carbohydrates to fats is 0.84:14.16, which simplifies to approximately 1:17.
However, this option is not available in the choices given. It seems there might be a mistake in the question or the given choices.
Similar Questions
The increase in cardiac output that occurs during exercise is due to_________
During heavy-intensity exercise, increases in cardiac output are associated with increases in_________a.the % of cardiac output increases, and the volume of blood increasesb.the % of cardiac output decreases, and the volume of blood increasesc.the % of cardiac output is unchanged, and the volume of blood is unchangedd.both systolic pressure generation and stroke volume.
The increase in cardiac output that occurs during exercise is due to_________a.both an increase in mean arterial pressure and a decrease in vascular resistance.b.an increase in mean arterial blood pressure only.c.a decrease in vascular resistance only.d.an increase in heart rate and a decrease in mean arterial blood pressure.
The primary determinant of oxygen uptake during exercise is the:Group of answer choicesExercise power outputExercise durationRelative mix of CHO and fat
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