Humans have a predisposition to experience a drop in alertness and vigilance around midday, between six and eight hours after waking up. In fact, the word siesta comes from the Latin sexta, which in Ancient Rome referred to the sixth hour of the day from dawn; a time reserved for rest and relaxation. There are many markers we measure in the laboratory which indicate that this period is present, even without having eaten lunch, he states.
Since I was little, I would repeatedly snooze my alarm clock each morning until I had to get up. The evidence on whether this makes you feel more tired is mixed, but I would get stuck in a state of sleep inertia, prolonging the period of confusion and sleepiness when you first wake up. It left me feeling anxious, and I would struggle to focus all day.