Whenever the body is exposed to a constant stimulus, it acclimates to it (once again, homeostasis at work). Have you ever watched a baby sleep in a crowded, noisy airport? The ambient noise is very loud, but constant. The baby adapts by developing resistance to the noise. It basically just ignores it. Now imagine the same baby sleeping in a quiet house. A slight creak of the floorboards may be enough to wake him up. Even though it is not loud, it is very noticeable. The baby isn’t used to the noise. High persistent levels create resistance. Hormones work in exactly the same way.
