Lecture Notes: Excess Post-Exercise Oxygen Consumption (EPOC)

Introduction to EPOC

Definition: Excess Post-Exercise Oxygen Consumption
- Describes the body's recovery phase after physical activity
Commonly occurs:
- Between sprints, gym sets, at halftime, end of quarters/games
EPOC: Increased oxygen consumption post-exercise
- Fast and heavy breathing is indicative

Fatigue Mechanisms:
- ATP & PC Depletion: Occurs after high-intensity work (~10 seconds)
- Myoglobin Oxygen Loss: Myoglobin stores oxygen in muscles
- Glucose and Glycogen Depletion: Common in long-duration events (e.g., marathon)
- Lactic Acid Accumulation
Different Fatigue Causes for Different Athletes:
- 100m runner: ATP & PC depletion
- 400m runner: ATP & PC depletion and lactic acid accumulation
- Marathon runner: Myoglobin oxygen loss and glucose/glycogen depletion

Definition: Breathing fast and deep after exercise to increase oxygen levels
- Helps return the body to pre-exercise state
Oxygen Deficit: Difference between required and consumed oxygen during exercise
- Indicates anaerobic effort
EPOC Components:
- Fast Component (First 2-3 minutes):
  - Uses 1-4 litres of additional oxygen
  - Resynthesizes ATP & PC and replenishes myoglobin
  - 50% PC resynthesized in 30 seconds, remainder in next 2 minutes
- Slow Component:
  - Removes lactic acid, maintains ventilation and body temperature
  - Requires additional 5-8 litres of oxygen
  - Can take minutes to hours depending on exercise intensity

Lactic Acid Conversion:
- Converts to pyruvic acid, enters Krebs cycle
- Outcomes: Carbon dioxide, water, glycogen, glucose, protein

Warm-up: Increases oxygen delivery, minimizes oxygen deficit
Active Recovery/Cool Down:
- Facilitates quicker ATP & PC resynthesis, myoglobin replenishment
- Aids lactic acid removal, maintains ventilation and circulation
Training and Strategy:
- Specific training to recover quicker
- Use of timeouts, player rotations
Nutrition: Adequate intake of carbohydrates, proteins, glucose, glycogen