Pearson Edexcel GCSE (9-1) Physical Education (1PE0) · Spec C1 1.3.1, C1 1.3.2, C1 1.4.1 and C1 1.4.2
Aerobic and anaerobic exercise and short-term effects
Read the notes, then try the questions. Each one is marked the moment you press Check, and shows the right answer and why.
Key ideas
- Aerobic exercise uses oxygen: glucose + oxygen gives energy, carbon dioxide and water. A steady 5 km run is mostly aerobic.
- Anaerobic exercise happens when there is not enough oxygen for the energy needed. It makes lactic acid, which leads to fatigue. A 100 m sprint is mostly anaerobic.
- Carbohydrate can fuel both systems. Fats can only be used aerobically.
- In exercise, heart rate, stroke volume and breathing depth and rate all rise. Cardiac output = stroke volume x heart rate.
- After hard exercise, breathing stays high to repay the oxygen debt (EPOC) and remove lactic acid.
Key terms
- Aerobic
- With oxygen.
- Anaerobic
- Without enough oxygen.
- Lactic acid
- A by-product of anaerobic respiration that builds up and causes fatigue.
- Stroke volume
- The blood pumped by the heart in one beat.
- Cardiac output
- The blood pumped by the heart in one minute.
- Oxygen debt (EPOC)
- The extra oxygen taken in after exercise to recover.
- Steady state
- When heart rate levels off during exercise at a constant pace.
Common mistakes
- Saying lactic acid is made by aerobic respiration. It comes from anaerobic.
- Mixing up stroke volume (one beat) and cardiac output (one minute).
- Giving the same reason twice for why breathing stays high after exercise. Use two different ones: repay oxygen debt and remove lactic acid.
Exam tip
Always give the direction of change and then the reason. For example: 'Heart rate increases because the muscles need more oxygen.' Use Q = SV x HR when the question gives numbers.
Free practice questions
7 questions, 10 marks. Answer, then press Check. The marking guide explains how the marks are worked out. Nothing is saved.
- Question 1 · Multiple choice[1 mark]
Tariq, 16, sprints 100 m. Which by-product forms in his muscles because the oxygen supply is insufficient?
- Question 2 · Multiple choice[1 mark]
Which activity is mostly aerobic for Lena, 15?
- Question 3 · Fill the gaps[1 mark]
Aerobic respiration: glucose + ___ gives energy, carbon dioxide and water.
Word bank: lactic acid · fat · oxygen · nitrogen
- Question 4 · Matching[4 marks]
Match each term to its correct description.
- Question 5 · Fill the gaps[1 mark]
Cardiac output = stroke volume x ___.
Word bank: heart rate · blood pressure · tidal volume · breathing rate
- Question 6 · Multiple choice[1 mark]
Rosa, 14, finishes a hard 400 m race. What is her oxygen debt (EPOC)?
- Question 7 · Multiple choice[1 mark]
Which pair of changes happens to Ruth's breathing during a 5 km run?