If you want to sleep the “exact” optimum amount of time every afternoon, follow these steps: Grab a set of keys or a small metallic object; Sit or lie down in a comfortable position but extend the hand that’s holding the metallic object outwards, away from the bed or armchair so that after you fall asleep, the keys or that object, will fall to the ground on a hard surface and produce a loud noise; Right when your hand relaxes, you enter the deep sleep phase and this is the best time to wake up before your body starts producing analgesics for the fourth stage of deep sleep.
Metallic object nap
