Question

Why does anaerobic respiration occur during vigorous exercise?

Answer 1

This is because,during vigorous excercise,oxygen supply is smaller than body requirement of oxygen and therefore anaerobic respiration occur .

Since anaerobic respiration occurs in the absence of oxygen.

Answer 2

Because the body supply of oxygen is less than the body requirement of oxygen for aerobic respiration.

During a strenous activity,the supply of oxygen do not reach body requirement for aerobic respiration to occur, that is why ,therefore fermentation anaerobic respiration occurs and the end product is lactic acid which then accumulates in the muscles.