Oxygen Debt - GCSE Biology Definition
Reviewed by: Lára Marie McIvor
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Oxygen debt occurs when the body cannot supply enough oxygen to meet its energy demands, often during exercise. As a result, the muscles carry out anaerobic respiration, which does not require oxygen but produces lactic acid as a by-product. This lactic acid can cause muscle fatigue and discomfort. After exercise, extra oxygen is needed to break down the lactic acid and restore the body to its normal state. This is why breathing and heart rate remain high for a while after intense activity—to “repay” the oxygen debt.
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