Explaining the Effect of Physical Activity on Heart Rate (Cambridge International IGCSE Biology)

Explaining the effect of physical activity on heart rate: Extended

Spec point — 9.2.11 · Explain the effect of physical activity on the heart rate

Extended Tier Only

• Heart rate increases during exercise to increase blood flow to the working muscles

• This is important for several reasons:

  • to provide the muscles with enough nutrients and oxygen for increased respiration
  • to remove waste products at a faster rate

• Following exercise, the heart continues to beat faster for a while:

  • to ensure that all excess waste products are removed from muscle cells

  • to deliver extra oxygen to the muscle cells to pay off the oxygen debt accumulated when oxygen levels are not high enough to support aerobic respiration

    • The extra oxygen is used to break down the lactic acid that has been built up in cells as a result of anaerobic respiration