After a vigorous exercise or work, we feel pain in muscles. What is the relationship between pain and respiration? (AS1)

1. Our body meets its energy requirement by aerobic respiration.

2. But under some situations, anaerobic respiration takes place in our body.

3. During vigorous exercise oxygen used up faster than the normal to meet the increased energy need.

4. Therefore, anaerobic respiration takes place in human muscles to produce more energy.

5. Due to the anaerobic respiration in the muscles glucose is converted into lactic acid with the release of a small amount of energy.

6. The accumulation of lactic acid in the muscles causes muscular pains or cramps