Question

b) Our heart beats faster when we run.

Answer 1

Explanation:

During exercise, your body may need three or four times your normal cardiac output, because your muscles need more oxygen when you exert yourself. During exercise, your heart typically beats faster so that more blood gets out to your body.

Answer 2

Answer:

When you exercise, your muscles need even more oxygen because they are working harder. The faster your heart beats, the faster it can get more blood and oxygen to your muscles. And when you feel scared, angry, or excited, your brain also tells your heart to be faster.