Explain the relationship between ventilation rate and lactate levels during and after high-intensity exercise. (5 marks)
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- During high-intensity exercise, ventilation rate increases significantly. This occurs because working muscles require more oxygen and produce excess carbon dioxide.
- As intensity exceeds the aerobic threshold, lactate accumulates in the bloodstream. This happens due to insufficient oxygen for complete aerobic metabolism.
- The rising lactate levels cause blood pH to decrease, creating an acidic environment. As a result, hydrogen ions accumulate alongside lactate in the blood.
- This triggers the respiratory control centre to increase ventilation rate further. Therefore, rapid breathing helps buffer the acidity by expelling more carbon dioxide.
- The relationship creates a compensatory mechanism where higher lactate leads to increased ventilation. This process helps maintain blood pH within tolerable limits during intense exercise.
- After exercise ceases, ventilation remains elevated because lactate clearance continues. Consequently, breathing rate gradually returns to normal as lactate levels decrease during recovery.
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Sample Answer
- During high-intensity exercise, ventilation rate increases significantly. This occurs because working muscles require more oxygen and produce excess carbon dioxide.
- As intensity exceeds the aerobic threshold, lactate accumulates in the bloodstream. This happens due to insufficient oxygen for complete aerobic metabolism.
- The rising lactate levels cause blood pH to decrease, creating an acidic environment. As a result, hydrogen ions accumulate alongside lactate in the blood.
- This triggers the respiratory control centre to increase ventilation rate further. Therefore, rapid breathing helps buffer the acidity by expelling more carbon dioxide.
- The relationship creates a compensatory mechanism where higher lactate leads to increased ventilation. This process helps maintain blood pH within tolerable limits during intense exercise.
- After exercise ceases, ventilation remains elevated because lactate clearance continues. Consequently, breathing rate gradually returns to normal as lactate levels decrease during recovery.