Exercise Physiology Overview

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Questions and Answers

What is a significant disadvantage of swimming as an exercise method?

It can only be performed indoors.

It requires expensive equipment.

It can be stressful and may not accurately mimic human exercise. (correct)

It is not physically demanding.

Which of the following is a pro of treadmill running?

It requires less effort than swimming.

It allows control over the intensity and duration of exercise. (correct)

It is the least expensive exercise method.

Most animals excel at running on treadmills.

What is a drawback of voluntary wheel running?

It is too expensive to maintain.

It has limited relevance to human exercise due to extended running duration. (correct)

It requires complex equipment for accurate measurement.

It is highly stressful for the animals.

What is one advantage of in situ rat hindlimb perfusion?

It allows very tight control over the perfusate composition. Signup and view all the answers

What is a major disadvantage of ex vivo isolated muscle incubation?

It is limited to only a few types of muscles. Signup and view all the answers

Which exercise method is generally considered the least stressful for animals?

Voluntary wheel running Signup and view all the answers

Which method poses the greatest challenge in quantifying the amount of exercise completed?

Swimming Signup and view all the answers

Which of the following options describes a limitation of treadmill running?

It can be stressful for animals, but less so than swimming. Signup and view all the answers

What is the purpose of a flow meter in open-circuit spirometry?

To measure the volume of air breathed Signup and view all the answers

Which component of open-circuit spirometry is responsible for assessing oxygen and carbon dioxide levels?

Analyzers Signup and view all the answers

What is a disadvantage of using open-circuit spirometry?

It may lead to hyperventilation Signup and view all the answers

What does the respiratory exchange ratio (RER) indicate?

The type of fuel being oxidized Signup and view all the answers

How is energy expenditure calculated from VO2?

By converting liters of oxygen to calories Signup and view all the answers

Which factor is indicated as the major limit to endurance performance according to Bengt Saltin?

Oxygen supply Signup and view all the answers

What effect does phlebotomy have according to the study by Bonne et al.?

It eliminates the maximal cardiac output response to training. Signup and view all the answers

What is the primary function of catecholamines during exercise in the liver?

Increase hepatic glucose production Signup and view all the answers

Which receptor type is primarily responsible for catecholamine response in muscle during exercise?

Beta 2 receptors Signup and view all the answers

What happens to norepinephrine levels during exercise as compared to epinephrine levels?

Norepinephrine circulates at higher levels Signup and view all the answers

How does exercise training affect liver sensitivity to catecholamines?

It reduces liver sensitivity to catecholamines Signup and view all the answers

What is a significant early response to catecholamines during exercise?

Increased glycogenolysis Signup and view all the answers

Which hormone is primarily released from the adrenal medulla?

Epinephrine Signup and view all the answers

Which of the following substrates can be used for gluconeogenesis under catecholamine influence?

Amino acids Signup and view all the answers

What primarily stimulates the release of epinephrine?

Norepinephrine Signup and view all the answers

What is the primary fuel source at rest for the body?

Fat oxidation Signup and view all the answers

Which factors influence the type of fuel used during exercise?

Intensity of exercise Signup and view all the answers

In which exercise intensity range is the 'Fat Burning Zone' identified?

40-60% VO2 max Signup and view all the answers

Which of the following is a criterion for determining maximum oxygen consumption (VO2 max)?

Blood lactate concentration > 8 mmoles/L Signup and view all the answers

What benefit is similar between moderate continuous exercise and HIIT programs over 12 weeks?

Body weight loss Signup and view all the answers

What is considered the best indicator of survival in patients with cardiovascular disease?

Cardiorespiratory fitness Signup and view all the answers

What percentage of energy expenditure is derived from fat oxidation at rest?

85% fat, 15% carbohydrate Signup and view all the answers

How is VO2 max expressed?

In both absolute and relative terms Signup and view all the answers

Study Notes

Swimming

Often strenuous exercise.
May not mimic human response.
Inexpensive.

Treadmill Running

Mimics human exercise studies.
Can be costly.

Voluntary Wheel Running

Inexpensive, not stressful.
Mice run long durations.

In Situ Rat Hindlimb Perfusion

Tight control over perfusate.
Less physiological; non-physiological stimulation conditions.

Ex Vivo Isolated Muscle Incubation

Tight control over incubation medium composition.
Less physiological than in situ perfusion.

Energy

Indirect Calorimetry is a technique to measure energy expenditure.
“Metabolic Cart” - measures volume of air, oxygen, and carbon dioxide.
Open-circuit spirometry uses ambient air.

Indirect Calorimetry Continued

Requires a “metabolic cart” system.
Disadvantages include hyperventilation, airtight mask fit, and mask comfort.
Advantages include portability, wide variety of activity applications, and substrate determination (fat/carb).

Comprehensive Lab Animal Monitoring System (CLAMS)

Indirect calorimetry system that collects data every 10 minutes.
Light beams estimate physical activity levels.

Basic Whole Body Metabolic Measurements

VO2 is used to calculate energy expenditure.
Thermal equivalent of O2 is approximately 5 kcal per L O2.
Primary fuel at rest is fat oxidation.
Fuel selection during exercise is influenced by intensity, duration, diet, and training status.

The “Fat Burning” Zone

Exercise intensity of 40-60% VO2 max.
High intensity exercise may provide similar benefits for body weight loss, fat loss, and preservation of fat-free mass compared to moderate continuous exercise.

VO2max

Maximum oxygen consumption/aerobic capacity.
Standardized progressive test until failure.
Optimal test length is 10-12 minutes.
Indicative of aerobic fitness and health.
Expressed in absolute (L/min) or relative (ml/kg/min) terms.

Limits of VO2 Max

Oxygen supply (central), and oxygen demand (peripheral).

Oxygen Supply (Central)

Hormones: Norepinephrine, epinephrine, glucagon, and insulin.
Fuel mobilization: liver, adipose, and muscle.
Delivery: Cardiovascular system.
Fuel utilization: Skeletal muscle.

Catecholamines

Epinephrine and norepinephrine.
Increased circulating levels during exercise.
Epinephrine levels are much higher than norepinephrine.

Catecholamines - Liver

Increased hepatic glucose production.
Increased glycogenolysis.
Increases gluconeogenesis.

Exercise Training and Catecholamines

Blunted catecholamine response.
Reduced liver sensitivity to epinephrine and norepinephrine.
Compensatory mechanisms may exist.

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Description

This quiz covers various forms of exercise including swimming, treadmill running, and voluntary wheel running, along with their physiological impacts. It also delves into energy expenditure measurement techniques like indirect calorimetry and metabolic carts. Test your knowledge on these important aspects of exercise physiology!