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Questions and Answers
What occurs to oxygen uptake (VO2) during increased exercise intensity?
What occurs to oxygen uptake (VO2) during increased exercise intensity?
How does the respiratory system respond to increased exercise intensity?
How does the respiratory system respond to increased exercise intensity?
What is the effect of exercise on the arterial-venous oxygen content difference (A-V) O2?
What is the effect of exercise on the arterial-venous oxygen content difference (A-V) O2?
What primarily stimulates the increase in ventilation during exercise?
What primarily stimulates the increase in ventilation during exercise?
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What adaptation occurs in the lungs to enhance oxygen diffusion during exercise?
What adaptation occurs in the lungs to enhance oxygen diffusion during exercise?
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What happens to cardiac output during exercise?
What happens to cardiac output during exercise?
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What physiological change aids in higher oxygen extraction during exercise?
What physiological change aids in higher oxygen extraction during exercise?
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What factor is necessary for increased oxygen consumption during exercise?
What factor is necessary for increased oxygen consumption during exercise?
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What is the maximum heart rate allowed in a person, based on their age?
What is the maximum heart rate allowed in a person, based on their age?
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Which hormone levels are known to increase during exercise?
Which hormone levels are known to increase during exercise?
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What physiological change occurs rapidly within the first few weeks of training?
What physiological change occurs rapidly within the first few weeks of training?
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Which of the following is a structural response to regular physical training?
Which of the following is a structural response to regular physical training?
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What happens to stroke volume as exercise intensity increases?
What happens to stroke volume as exercise intensity increases?
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What adaptation is associated with cardiac hypertrophy due to regular training?
What adaptation is associated with cardiac hypertrophy due to regular training?
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During exercise, the increase in cardiac output (CO) after training relies more on which factor?
During exercise, the increase in cardiac output (CO) after training relies more on which factor?
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Which of the following describes changes in muscle fibers as a result of training?
Which of the following describes changes in muscle fibers as a result of training?
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Study Notes
Exercise Physiology
- Physiological responses during incremental exercise intensity are covered.
- Maximum oxygen uptake (VO2 max) denotes the point where an individual can't increase oxygen consumption further.
Metabolic Response
- Oxygen uptake (VO2) increases with exercise intensity until it reaches a maximum or plateau.
- The respiratory system provides more oxygen, the cardiac system distributes more blood to active muscles, and the muscle metabolic systems use the increased oxygen.
Oxygen Consumption Relative to Exercise Intensity
- A graph shows oxygen consumption increasing with exercise intensity until it plateaus at VO2 max.
Respiratory Response
- Extra oxygen is delivered to the blood during exercise.
- Ventilation increases proportionally with oxygen uptake (VO2).
- Initially, ventilation increases due to both increased tidal volume and respiratory rate.
- But as exercise continues, tidal volume plateaus, and further increase in ventilation is solely due to a higher respiratory rate.
Three-Fold Increase in Oxygen Diffusing Capacity
- Pulmonary capillary perfusion increases, providing a greater surface area for oxygen diffusion.
Arterial-Venous Oxygen Content Difference (A-V O2)
- The difference between arterial and venous blood oxygen content.
- Exercise widens this difference for greater oxygen delivery.
- Increased blood flow to working muscles leads to higher oxygen extraction.
Cardiac Response
- Cardiac output (CO) increases in response to exercise to supply more blood to working muscles.
- Heart rate increases linearly with oxygen uptake, while stroke volume increases initially and reaches a plateau.
- The increase in CO is primarily based on heart rate after stroke volume reaches its peak.
- Maximum heart rate (MHR) is approximately 220 minus age.
Endocrine Response during Exercise
- Exercise raises blood levels of growth hormone, thyroxine, and aldosterone.
Physiological Adaptations to Regular Physical Training (Regulatory)
- Rapid responses within a few weeks of training.
- Shift from sympathetic to parasympathetic activity.
- Redistribution of blood flow.
- Initiation of sweating at a lower core temperature.
- Increased sensitivity to insulin to improve glucose tolerance at lower insulin levels.
Physiological Adaptations to Regular Physical Training (Structural)
- Slow changes over months or years.
- Increased muscle mass, cardiac tissue, and bone with increased capillary blood supply.
- Increased maximum oxygen consumption from increased enzyme activity in glycolysis.
- Increased aerobic capacity with higher myoglobin, Krebs cycle & mitochondrial function, with fat utilization sparing glycogen for anaerobic activity.
- Muscle fiber changes (mainly hypertrophy with more myofibrils, mitochondria, and stored ATP, glycogen, and triglycerides).
Respiratory Adaptations (Structural)
- Slower and deeper breathing pattern.
Cardiac Adaptations (Structural)
- Increase in the heart size (athlete's heart).
- High ventricular preload over time is the trigger for cardiac hypertrophy.
- Increased coronary artery cross-section along with higher capillary density and myocardial perfusion.
Possible Limitations to Maximal Oxygen Consumption
- Cardiovascular system components include central circulation (heart rate, stroke volume, hemoglobin concentration), peripheral circulation (flow to non-exercising areas, muscle capillary density, oxygen diffusion, and extraction), and hemoglobin-oxygen exchange).
- Respiratory factors include oxygen diffusion, ventilation, alveolar ventilation-perfusion ratio, and arteriovenous oxygen difference.
- Skeletal muscle factors include enzymes and oxidative potential, energy stores and delivery, myoglobin, and mitochondria number and size.
Physiological Adaptations to Regular Physical Training (Continued)
- Increased cardiac output during exercise depends more on stroke volume increase than heart rate increase during training.
- Athletes have a larger stroke volume at a lower heart rate, resulting in a 40-50% greater heart-pumping capacity.
- Autonomic activity modification reduces catecholamine output and its sensitivity, leading to a lower heart rate.
Effect of Drugs on Exercise Performance
- Caffeine in small quantities can improve exercise performance.
- Male sex hormones (androgens) can increase muscle strength but cause liver damage and affect reproductive health.
- Cocaine use in exercise performance can be deadly.
Key Points
- Alterations in metabolism, heart, and respiration occur during exercise.
- Physiological adaptations to exercise are regulatory and structural.
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Description
Explore the physiological and metabolic responses during exercise, focusing on oxygen uptake and the respiratory adjustments to varying exercise intensities. This quiz covers concepts related to VO2 max and how the body adapts to strenuous physical activity.
