Question

What happens in rigorous exercise?
A) Rate of metabolism increases
B) Need of oxygen increases
C) Both A and B
D) None of the above

Answer 1

Oxygen is the most essential element required for the metabolism of our body. In case of rigorous exercise or increased physical work, the body starts panting, which is shortening of breath and increased breathing. The muscles become fatigued.

Complete answer:
Rigorous activity is the physical activity done which requires a large amount of effort. This leads to deep and rapid breathing, sweating instantly and also, we are unable to say a word without pausing for breath. Some examples of rigorous activity are jogging, running, swimming very fast etc.

In case of rigorous activity, the lactic acid starts accumulating in the muscles as a result of anaerobic respiration which leads to fatigue. As a result , the demand for oxygen increases in our body and the muscle cells respire more than usual. The muscles release more carbon dioxide than normal.

Thus, a person involved in rigorous activities starts panting and taking shorter breaths so that he/she can breathe in more oxygen. As more oxygen is required by the body, the metabolism rate of the body increases, the heart starts pumping more blood to the lungs. This results in rapid heartbeat and heavier breathing. As more oxygen is taken, the amount of glucose broken down by the cells will be higher and more energy will be released.

Therefore the correct answer is option (C).

Note: In case of anaerobic respiration, the glucose is broken down into lactic acid in the absence of oxygen. Too much formation of lactic acid leads to fatigue. This process is known as fermentation. In the case of fungi, the glucose is broken down into ethanol and carbon dioxide.