Your baby has a good sense of smell from the start. She gets to know your scent on Day 1 and probably recognizes the scent of other people in her life within about a week. Babies are especially sensitive to the smell of breast milk and can even distinguish it from formula , says Dr. Tapas.
As an intermediate pathway between the phosphagen and aerobic system, anaerobic glycolysis can produce ATP quite rapidly for use during activities requiring large bursts of energy over somewhat longer periods of time (30 seconds to three minutes max, or during endurance activities prior to steady state being achieved).
Exercises that are less intense but last longer allow the body to give the muscles oxygen as they are using it up, and keep them doing aerobic respiration. More intense exercises use up the oxygen in the cells faster than it can be replaced, so the cells divert to anaerobic respiration to get the energy they need.