Exercise

• What happens to your muscles when you exercise?


  Some of your muscles contract more frequently than normal.
• Why do your muscles need more energy during exercise?


  Because they contract more frequently than normal.
• What does the increase in respiration in your cells require?


  More oxygen to be delivered to the cells.
• How do your breathing and heart rates change during exercise?


  They increase to get more oxygen into the blood quickly.
• What is the role of oxygenated blood during exercise?


  It removes CO₂ and other waste products quickly.
• What happens to your muscles during vigorous exercise like sprinting?


  They start working anaerobically due to insufficient oxygen supply.
• Why is anaerobic respiration not the best way to get energy from glucose?


  Because lactic acid builds up in the muscles, causing pain.
• What is muscle fatigue and what causes it?

  Muscle fatigue is when muscles get tired and stop contracting efficiently after long periods of exercise.
• What is an oxygen debt?


  It is the amount of extra oxygen needed to react with lactic acid and remove it from the cells.
• How does oxygen react with lactic acid?


  It forms harmless CO₂ and water.
• What must you do to repay the oxygen debt after exercising?


  You have to keep breathing hard for a while to get more oxygen into your blood.
• What happens to your pulse and breathing rate after intense exercise?


  They stay high while there are high levels of lactic acid and CO₂.
• How does the body cope with high levels of lactic acid?


  The blood transports lactic acid to the liver, where it is converted back to glucose.
• How can you measure breathing rate?


  By counting breaths.
• How can you measure heart rate?


  By taking the pulse.
• How do you take your pulse?


  Put two fingers on the inside of your wrist or neck and count the number of pulses in 1 minute.
• What is a suggested method to investigate the effect of exercise on the body?


  1. Take your pulse after sitting for 5 minutes.
  2. Take your pulse after 5 minutes of gentle walking.
  3. Take your pulse after 5 minutes of slow jogging.
  4. Take your pulse after running for 5 minutes.
  5. Plot results in a bar chart.
• What trend is observed in pulse rate with increasing exercise intensity?


  The pulse rate increases as exercise intensity increases.
• How can random errors be reduced in measuring pulse rates during exercise?


  • Conduct the experiment as a group.
  • Plot the average pulse rate for each exercise.
• What does very vigorous exercise lead to in terms of respiration?


  It leads to anaerobic respiration and an oxygen debt.
• Which type of exercise would likely lead to the highest concentration of lactic acid in the blood after 10 minutes?


  Very vigorous exercise like sprinting.