Cardiovascular Physiology Overview

VO2max Definition

• VO2max is the maximum amount of oxygen a person can intake, transport, and utilize during exercise.

Left Ventricular Hypertrophy Comparison

• Eccentric Hypertrophy:
  • Internal diameter of the left ventricle (LV) increases.
  • The thickness of the LV remains the same.
  • Cause: endurance training.
  • Regulator: increased end-diastolic volume (EDV, preload). This can lead to increased stroke volume (SV) as the heart can pump more blood with each beat.
• Concentric Hypertrophy:
  • Internal diameter of the LV remains constant.
  • The thickness of the LV wall increases.
  • Cause: resistance training.
  • Regulator: increased ventricular contractility.
• Pathological Hypertrophy:
  • Characterized by a decrease in stroke volume and an increase in wall size and thickness.
  • Cause: underlying heart disease.

Functional Sympatholysis

• Localized vasodilation and vasoconstriction to redirect blood flow to working muscles during exercise. This happens even when the body tries to conserve blood elsewhere.
• Areas primarily affected: working muscles.

Protein Synthesis Activation

• Protein feeding and resistance exercise activate protein synthesis.

Training Status and Protein Activation Duration

• Untrained: Protein synthesis activation can last up to 48 hours or more after exercise.
• Trained: Protein synthesis activation lasts from 12 to 24 hours after exercise.

Anabolic Resistance

• How age and dieting can change the body's response to anabolic stimuli.
• Response to anabolic stimuli decreases.

Net Protein Balance

• Positive net PB (anabolic): When protein synthesis outweighs protein breakdown.
• Negative net PB (catabolic): When protein breakdown outweighs protein synthesis.
• Components: Whole-body protein synthesis (WBPS) - Whole-body protein breakdown (WBPB); Muscle protein synthesis (MPS) - Muscle protein breakdown (MPB).

Crossover Effect

• Shift from using fat to using carbohydrates for fuel as exercise intensity and duration increase.

Motor Unit Components

• A motor neuron and the muscle fibers it innervates make up a motor unit. A motor unit is the smallest functional unit in a muscle.

Size Principle

• The body selects and recruits smaller, energy-efficient muscle fibers first for smaller tasks, then progressively recruits larger, stronger muscle fibers as the demands increase. The body needs to decide which helper muscles (muscles used as helpers for a specific task) are needed for the job.

Carbohydrate Metabolism (Glycogen vs. Glucose)

• Glycogen Utilization: Net gain of 3 ATP.
• Glucose Utilization: Net gain of 2 ATP.
• Starting with glycogen requires fewer enzymatic steps.

Cardiac Cycle Phases

• Four phases of the cardiac cycle, pressure differences, blood flow, diastole vs. systole; etc. are described in the document.

Contraction Types

• Isometric: No shortening or lengthening of the muscle.
• Isokinetic: Constant speed of contraction.
• Isotonic: Constant tension during contraction, with shortening or lengthening of the muscle.

Hypertrophy Types

• Transient Hypertrophy:
  • Increased muscle size during and immediately after a single exercise bout.
  • Also known as sarcoplasmic hypertrophy.
  • Fluid accumulation in the sarcoplasm.
• Chronic Hypertrophy:
  • Increase in muscle size with long-term resistance training.
  • Also known as myofibrillar hypertrophy.
  • Increase in muscle fiber size.
  • Types of Myofibrillar Hypertrophy (2):
    • Parallel: Sarcomeres added parallel to existing ones, increasing force and torque production. This type of hypertrophy is seen with heavy resistance training (greater than 80% of one-repetition max, or 1RM).
    • Series: Sarcomeres added end-to-end, making the myofibril longer. This is associated with power training using resistance between 40-60% of 1RM.

HRV (Heart Rate Variability)

• HRV measures how much your heart rate changes between beats— a measure of how well your body is recovering from stress and exercise.
• High HRV: Flexible response to demands, good recovery potential.
• Low HRV: Stiff response to demands, poor recovery potential, struggle to recover from overtraining.

Energy Systems and Exercise Duration

• The duration of exercise each energy system supplies the body is described.

Exercise-Induced Muscle Burning

• Accumulation of H+ ions, decreasing pH in the sarcoplasm and leading to muscle burning.

Nervous System and Heart Rate During Exercise

• Raising HR (during exercise): Decreased parasympathetic activity (withdrawal) allows sympathetic acceleration, increasing heart rate.
• Lowering HR (post-exercise): Parasympathetic activity returns and sympathetic stimulation lessens, decreasing heart rate.

Exercise Modality and Blood Pressure Changes

• Aerobic Exercise: Significant increase in systolic blood pressure (SBP) due to increased cardiac output to meet the working muscles' increased oxygen demand. Diastolic blood pressure (DBP) shows little to no change or a slight increase due to vasodilation.
• Resistance Training: SBP and DBP can increase, particularly during isometric exercises, and influenced by the factors such as exercise intensity, age, fitness level, and underlying health conditions.

Four Regulators of Stroke Volume

• (1) Preload (EDV): Volume of blood in ventricles at end of diastole; stretch in the ventricles before contraction. ↑ Preload = ↑ Stroke Volume.
• (2) Cross-sectional area: Myocardium thickness and size; chronic adaptations to training. ↑ cross-sectional area = ↑ Stroke Volume.
• (3) Ventricular Contractility: Ability of myocardium to generate force and contract. Increased contractility = Increased stroke volume.
• (4) Afterload: Resistance the heart must overcome to eject blood; primarily arterial pressure. ↑ afterload = ↓ stroke volume.

Cardiac Equations

• Equations for cardiac output, stroke volume, rate pressure product, and mean arterial pressure are listed and explained.

Action Potential Propagation

• Steps in action potential propagation from axon hillock to motor endplate.

Muscle Contraction Steps

• Steps of muscle contraction, including the events that cause muscle contraction.

Muscle Contraction Phases

• Explanation of the phases in muscle fiber contraction, including the power stroke, calcium ion release, and events associated with returning the fiber to a resting state.

Other Information (Diagram Label, Cardiac Test Data, Calculations, Etc.)

• Information needed to calculate cardiac output, ejection fraction, and other variables related to cardiac function. Other factors like dehydration and SNS activation are included.

This quiz explores key concepts in cardiovascular physiology, including definitions of VO2max and comparisons between various types of left ventricular hypertrophy. It also covers the mechanism of functional sympatholysis and its significance during exercise. Test your knowledge on these fundamental topics in heart function and exercise physiology.