Question

Radha was running on a treadmill at a great speed for 15 minutes continuously. She stopped the treadmill and abruptly came out. For the next few minutes, she was breathing heavily/fast. Answer the following questions.
a.What happened to her muscles when she did strenuously
exercise?
b.How did her breathing rate change?

Answer 1

Red muscle fibres and white muscle fibres

There are two types of muscle fibres;
Red muscle fibres have abundant amounts of myoglobin and mitochondria. These fibres can contract for a longer duration and the energy for contraction is obtained through aerobic oxidation.
White muscle fibres have less amount of myoglobin and mitochondria, they obtain the energy from anaerobic respiration which leads to the production of lactic acid. Muscles get fatigued due to the accumulation of lactic acid.

Summary

During strenuous exercise Radha’s muscles are getting energy through anaerobic respiration leading to the production of lactic acid and its accumulation makes the muscles fatigued. So she stops and abruptly comes down from the treadmill.

Introduction to oxygen debt

During strenuous exercise muscles get energy through anaerobic respiration leading to the production of lactic acid and its accumulation makes the muscles fatigued. The consumption of oxygen increases to oxidise the accumulated lactic acid this phenomenon is referred to as oxygen debt.

Summary

Radha’s breathing rate increases so that more oxygen can be taken in for the oxidation of lactic acid.