Exercise

• Exercise

  When you exercise, your body responds in different ways to get enough energy to your cells
• What happens when you exercise

  1. Muscles need energy from respiration to contract

  2. Increase in respiration in cells means need more oxygen

  3. Breathing rate and breath volume increase to get more oxygen

  4. Heart rate increases to transport oxygen and CO2 more quickly

  5. Body can't supply oxygen quickly enough, so start respiring anaerobically

  6. Lactic acid builds up in muscles, which is painful

  7. Muscle fatigue causes muscles to stop contracting efficiently
• Lactic acid is formed from the incomplete oxidation of glucose
• Oxygen debt

  The amount of extra oxygen your body needs to react with the build up of lactic acid and remove it from the cells
• What happens after anaerobic respiration

  1. Have to keep breathing hard to get more oxygen into blood

  2. Pulse and breathing rate stay high whilst there are high levels of lactic acid and CO2

  3. Blood transports lactic acid to liver where it is converted back to glucose
• Investigating the effect of exercise on the body

  1. Measure breathing rate by counting breaths

  2. Measure heart rate by taking the pulse

  3. Take pulse after sitting, walking, jogging, running and plot results in a bar chart

  4. Pulse rate increases with more intense exercise as body needs more oxygen and to remove more CO2
• To reduce the effect of any random errors, do the experiment as a group and plot the average pulse rate for each exercise
• At the end of a sprinting race, athletes often breathe hard to remove the lactic acid that's built up in the muscles