Question

when the man is walking up hills, his rate of breathing was increased What is the Reason

Answer 1

Ans. The rate of breathing increases while walking uphill at a normal pace in Mountains because of the following reasons -
As we go up the hill above sea level, the concentrations of O2 is greatly reduced. So we have to breathe more to get required amount of O2.
While walking the uphill, a lot of oxygen is used by our body to release energy from glucose.
This leads to lack of O2 in the cells.
Hence, to increase the amount of O2 intake there is an increase in breathing rate during walking uphill.