Exercise Physiology Notes

Exercise Physiology Overview

  • Physiology: Study of body functions for maintaining life.
  • Exercise Physiology: Focuses on how exercise affects bodily functions and adaptations.

Key Discussions in Exercise Physiology

  • Acute Exercise: Responses during a single exercise session.
  • Chronic Exercise: Adaptations from repeated exercise (training).
  • Environmental Responses: Effects of exercising in different environments.
  • Population Responses: Variability of exercise effects across demographics.

Core Principles of Exercise Physiology

  1. Homeostasis:

    • Definition: Maintaining a stable internal environment during rest.
    • Balancing factors: Temperature, breathing, circulation.

  2. Overload Principle:

    • Continuous overload leads to adaptations over time.
    • Sequence: Stress > Acute Response > Chronic Adaptation.

  3. Specificity Principle:

    • Adaptations are specific to the type of stress applied (e.g., single leg vs. double leg training).
    • Different adaptations for cardiovascular endurance vs. muscle strength.

  4. Reversibility Principle:

    • Inactivity leads to a decline in fitness (muscle mass and cardiovascular fitness).

  5. Individuality Principle:

    • Everyone's physiological response to training varies based on genetics.
    • General responses may be similar but individual adaptations differ.

Biological Control Systems

  • Control Systems: Maintain homeostasis via interconnected components.
  • Components include:
    • Stimulus: The event activating the response.
    • Sensor: Monitors and sends real-time data to the control center.
    • Control Center: Processes data and issues commands.
    • Effector: Executes the response.
Types of Control Systems
  • Negative Feedback:
    • Reverses initial stimulus (e.g., body temperature regulation).
  • Positive Feedback:
    • Enhances the initial stimulus (e.g., childbirth contractions).

Homeostasis vs. Steady State

  • Homeostasis: Balance at rest across the whole body.
  • Steady State: Balance achieved during exercise for individual physiological elements.

Cardiovascular System Overview

  • Functionality: Transport oxygen, nutrients, and remove waste from tissues.
  • Key Adjustments during exercise:
    • Increased cardiac output, changes in blood pressure and flow.
Heart and Blood Flow
  • Heart Structure: Composed of 4 chambers (2 atria and 2 ventricles).
  • Cardiac Output (Q): Volume of blood pumped by the heart per minute, increases with exercise.
    • Q = HR x SV (Heart Rate x Stroke Volume).
Determinants of Stroke Volume
  1. Preload: Volume of blood in ventricles pre-contraction.
  2. Contractility: Strength of ventricular contraction, affected by sympathetic stimulation.
  3. Afterload: Pressure the heart must work against to pump blood.

Blood Pressure Regulation

  • Blood Pressure Measurements: Systolic over diastolic (e.g., 120/80 mmHg).
    • MAP Calculation: MAP = DBP + 0.33 × (SBP - DBP).
  • Short-term regulation via the sympathetic nervous system; long-term via the kidneys.

Respiratory Physiology Overview

  • Functions: Gas exchange, acid-base balance regulation.
  • Ventilation: Movement of air in/out of lungs.
  • Respiration: Exchange of gases between the lungs and blood.
Respiratory System Structure
  • Key components include nose, mouth, pharynx, larynx, trachea, bronchi, lungs, alveoli, and ventilatory muscles.
  • Pulmonary Respiration: Oxygen infused into blood; CO2 removed.

Energy Metabolism Overview

  • Bioenergetics: Study of energy production and transfer in organisms.
  • ATP Production:
    • ATP is synthesized from ADP and phosphate through energy inputs.
  • Energy Systems:
    • ATP-PC System: Immediate ATP supply from stored ATP and phosphocreatine (lasts ~10 seconds).
    • Glycolytic System: Provides ATP through anaerobic glycolysis (20 sec - 3 min of high-intensity exercise).
    • Aerobic System: Utilizes oxygen for ATP production; predominant during moderate to low intensity.
      - Aerobic system phases: Formation of Acetyl-CoA, Krebs Cycle, Electron Transport Chain.
Summary of Energy Production
  • Energy is derived from carbohydrates, fats, and proteins to fuel exercise.
  • Carbohydrates serve as the primary source, while fats are significant for prolonged, lower-intensity exercise. Proteins are less critical but can be converted into energy pathways if needed.