Have someone else watch the clock while you count the beats. Now do an exercise, like jumping jacks, for one minute. Then check your pulse again. Children have faster pulses than adults. This is true even when children are resting.
Babies have even faster pulses.
So since babies are so small it takes less time. Once I did my jumping jacks my heart beat a lot faster. My jumping jacks made my heart work harder. Babies are smaller than kids and adults. Their hearts can pump blood faster through their little bodies.