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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Lára Marie McIvor

Reviewer: Lára Marie McIvor

Expertise: Biology, Psychology & Sociology Subject Lead

Lára graduated from Oxford University in Biological Sciences and has now been a science tutor working in the UK for several years. Lára has a particular interest in the area of infectious disease and epidemiology, and enjoys creating original educational materials that develop confidence and facilitate learning.

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