Their hearts can pump blood faster through their little bodies. The blood has a shorter way to go before it reaches the heart again. Adults blood has a longer way to go to reach the heart again because they have bigger bodies. Tony I see that my lungs have air turning into blood. Nzingha Children have faster pulses than Grown-up's pulses because they are younger.
Babies have even faster pulses because they are even younger.
I think why the babies have faster pulses is because when your inside your mommy's tummy you do a lot of exercise. The exercise is when you roll around and move that counts as an exercise. Why kids have 100,000 beating pulses because you don't do that much exercise in a day. Why old people have less beating pulses because they barely exercise, well maybe once or twice but not that much as a newborn baby that has more than 100,000 beating pulses. When you exercise your heart pumps faster.