# After a period of intense exercise, a person continues to breathe deeply and rapidly for several minutes even though the exercise has stopped. Explain why this happens in terms of anaerobic respiration and its products.

> Eduqas GCSE Biology — 1.2.1 Aerobic and anaerobic respiration · Explain · 4 marks

## Mark scheme (4 marks)

1. During intense exercise, muscles respire anaerobically (as oxygen supply is insufficient)
2. Lactic acid builds up / accumulates in the muscles
3. An oxygen debt is created (which must be repaid)
4. Continued deep and rapid breathing supplies the extra oxygen needed to break down / remove the lactic acid, repaying the oxygen debt

## Key terms

- [anaerobic respiration](https://www.gradenine.co.uk/glossary/anaerobic-respiration)

## Related

- [Revision notes for Eduqas GCSE Biology](https://www.gradenine.co.uk/learn)
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Source: [GradeNine](https://www.gradenine.co.uk/q/after-a-period-of-intense-exercise-4e05137c) · Published by Druglandscape Ltd.