The exponential rise in ventilation observed during incremental exercise (i.e., ventilatory threshold) is thought to be principally due to  a decrease in arterial PO 2. an increase in arterial PO 2. an increase in arterial pH. a decrease in arterial pH.

Which of the followig would increase the pH of the blood?   high intensity exercise resulting in the production of CO2. decreased ventilation causing a build up of CO2. increased ventilation at the lung to remove CO2. a higher ventilation to perfusion ratio (V/Q) in the lung.

Ventilation is increased the most by:Group of answer choicesincreases in arterial PO2.increases in arterial PCO2.decreases in arterial PO2.decreases in arterial PCO2.

The initial increase in heart rate at the onset of incremental exercise is due to:Group of answer choicesincreased plasma adrenalinereduced vagal activityincreased venous return due to activation of the muscle pump

The major stimulus for increased ventilation during exercise is:Group of answer choicesCO2 flux to the lungincreased blood lactatehypoxia

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