Cardiovascular Physiology During Exercise Quiz

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Questions and Answers

Which of the following is NOT a component of total energy expenditure?

Thermic effect of food

Muscle structure (correct)

Resting Metabolic Rate

Physical activity

What is the equation to calculate oxygen uptake using the Fick equation?

VO2 = Q x HR

VO2 = HR x SV

VO2 = SV x a-vO2 extraction

VO2 = Q x a-vO2 extraction (correct)

Which of the following is NOT a method used in the measurement of human work output and power?

Bench step

Arm ergometer

Spirometry (correct)

Cycle ergometer

How can energy expenditure be expressed in terms of kcal?

L min-1 Signup and view all the answers

What is the relationship between work rate and maximal oxygen uptake (VO2max) in subjects with different levels of physical conditioning?

Directly proportional Signup and view all the answers

During exercise, what percentage of cardiac output is typically directed towards working skeletal muscle?

80-85% Signup and view all the answers

What is the role of nitric oxide in blood flow regulation during exercise?

Promotes smooth muscle relaxation Signup and view all the answers

What is the average aortic blood pressure?

The pressure the heart must pump against to eject blood Signup and view all the answers

What is the relationship between aortic blood pressure and stroke volume?

As aortic blood pressure increases, stroke volume increases Signup and view all the answers

What is the effect of sympathetic stimulation on stroke volume?

Increases inward transport of extracellular calcium Signup and view all the answers

During exercise, stroke volume reaches a plateau at what percentage of VO2 max in untrained subjects?

40-60% Signup and view all the answers

What are the three main determinants of myocardial oxygen demand that increase during exercise?

Heart rate, myocardial contractility, ventricular work Signup and view all the answers

What is the relationship between cardiac output (Q), arterial-venous oxygen difference (a-vO2 difference), and oxygen consumption (VO2)?

VO2 = Q x a-vO2 difference Signup and view all the answers

During exercise, as exercise intensity increases, the venous hemoglobin saturation of blood decreases. True or false?

True Signup and view all the answers

What is the equation for calculating the double product (rate-pressure product) during exercise?

Double product = HR x systolic BP Signup and view all the answers

Which of the following is true about the effects of incremental exercise on cardiac output, heart rate, and stroke volume?

Cardiac output increases, heart rate increases, and stroke volume increases. Signup and view all the answers

During exercise, blood flow is redistributed in the body. Which of the following is true about the pattern of redistribution of blood flow?

Blood flow increases in the working muscles and decreases in the non-working muscles. Signup and view all the answers

What factors regulate local blood flow during exercise?

Changes in sympathetic and parasympathetic nervous system activity Signup and view all the answers

What are the hemodynamic differences between upper and lower limb exercise?

Upper limb exercise leads to a greater increase in cardiac output compared to lower limb exercise. Signup and view all the answers

What are the cardiovascular responses to prolonged exercise?

Increased heart rate and increased stroke volume Signup and view all the answers

During arm work, what is the main reason for the higher heart rate compared to leg work?

Increased sympathetic stimulation Signup and view all the answers

What is the formula to calculate stroke volume (SV)?

SV = End diastolic volume - End systolic volume Signup and view all the answers

What is the formula to calculate cardiac output (Q)?

Q = SV * HR Signup and view all the answers

What is the formula to calculate ejection fraction (EF)?

EF = SV / EDV * 100 Signup and view all the answers

What is the formula to calculate VO2max?

VO2max = Q * A-VO2 diff / 100 Signup and view all the answers

Which of the following is a stimulus for cardiac chamber enlargement in athletes heart?

Repetitive volume challenge during training Signup and view all the answers

What changes in left and right ventricular morphology can be seen as early as 3 months in athletes heart?

Increase in ventricular mass Signup and view all the answers

What distinguishes the physiologic adaptation to chronic exercise training from pathologic conditions associated with cardiac hypertrophy?

Increased compliance of the ventricular chamber Signup and view all the answers

What happens to VO2 max during detraining?

It decreases by 20% after 84 days Signup and view all the answers

What is the effect of detraining on the oxidative capacity of muscle?

It decreases Signup and view all the answers

Study Notes

Energy Expenditure and Oxygen Uptake

Total energy expenditure does not include thermic effect of food.
Oxygen uptake can be calculated using the Fick equation: VO2 = ( cardiac output x arterio-venous oxygen difference ).

Measurement of Human Work Output and Power

Methods used to measure human work output and power include Oxygen uptake, Blood lactate, and Heart rate, but not Electromyography (EMG).

Energy Expenditure and Kcal

Energy expenditure can be expressed in terms of kcal by multiplying oxygen uptake (in liters) by the caloric equivalent of oxygen (approximately 4.8 kcal/L).

Work Rate and Maximal Oxygen Uptake (VO2max)

Work rate and VO2max are highly correlated in subjects with different levels of physical conditioning.

Cardiac Output and Blood Flow Regulation

During exercise, approximately 80% of cardiac output is directed towards working skeletal muscle.
Nitric oxide plays a crucial role in blood flow regulation during exercise by causing vasodilation.

Aortic Blood Pressure and Stroke Volume

Average aortic blood pressure is approximately 100 mmHg.
Aortic blood pressure and stroke volume are directly related.

Sympathetic Stimulation and Stroke Volume

Sympathetic stimulation increases stroke volume.

Exercise and Stroke Volume

In untrained subjects, stroke volume reaches a plateau at approximately 40-50% of VO2max during exercise.

Myocardial Oxygen Demand

The three main determinants of myocardial oxygen demand that increase during exercise are Heart rate, Contractility, and Preload.

Cardiac Output, Oxygen Consumption, and Arterial-Venous Oxygen Difference

The relationship between cardiac output (Q), arterial-venous oxygen difference (a-vO2 difference), and oxygen consumption (VO2) can be described by the equation: VO2 = Q x (a-vO2 difference).

Exercise and Venous Hemoglobin Saturation

During exercise, as exercise intensity increases, venous hemoglobin saturation of blood decreases.

Double Product (Rate-Pressure Product)

The equation for calculating the double product (rate-pressure product) during exercise is: Rate-Pressure Product = Heart rate x Systolic blood pressure.

Incremental Exercise and Cardiovascular Responses

During incremental exercise, cardiac output, heart rate, and stroke volume all increase.

Redistribution of Blood Flow

During exercise, blood flow is redistributed from viscera and skin to working skeletal muscle.
Blood flow is redistributed in a pattern of increased blood flow to active muscles and decreased blood flow to inactive areas.

Regulation of Local Blood Flow

Local blood flow during exercise is regulated by Vasodilation, Vasopressin, and Baroreceptors.

Hemodynamic Differences between Upper and Lower Limb Exercise

Upper limb exercise results in higher heart rates and lower cardiac outputs compared to lower limb exercise.

Cardiovascular Responses to Prolonged Exercise

Cardiovascular responses to prolonged exercise include increased cardiac output, heart rate, and stroke volume.

Arm Work and Heart Rate

During arm work, the main reason for the higher heart rate compared to leg work is the smaller muscle mass of the arms.

Formulas for Cardiovascular Parameters

The formula for calculating stroke volume (SV) is: SV = End-diastolic volume - End-systolic volume.
The formula for calculating cardiac output (Q) is: Q = Heart rate x Stroke volume.
The formula for calculating ejection fraction (EF) is: EF = (Stroke volume / End-diastolic volume) x 100%.
The formula for calculating VO2max is: VO2max = (Cardiac output x Arterial-venous oxygen difference) / Body weight.

Athlete's Heart

A stimulus for cardiac chamber enlargement in athletes' heart is Chronic volume overload.
Changes in left and right ventricular morphology can be seen as early as 3 months in athletes' heart, including increased left ventricular wall thickness and chamber size.

Physiologic Adaptation to Chronic Exercise Training

What distinguishes the physiologic adaptation to chronic exercise training from pathologic conditions associated with cardiac hypertrophy is the absence of fibrosis and preserved cardiac function.

Detraining and VO2max

During detraining, VO2max decreases.

Detraining and Oxidative Capacity of Muscle

During detraining, the oxidative capacity of muscle decreases.

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Description

Test your knowledge on the redistribution of blood flow during exercise! Learn about how total peripheral resistance (TPR) decreases and blood flow increases to working skeletal muscles. Discover the changes in blood flow to different organs and their dependence on metabolic rate.