I’ve always loved spanish people for their siesta culture… Wikipedia defines the siesta as “a short nap taken in the early afternoon, often after the midday meal“ and explains that the word origin is “hora sexta”, meaning “sixth hour” (after the dawn, so about midday) in ancient latin language. Anyway, I’ve decided to stop yawning for a while and learn some interesting things related to naps 🙂
The first important thing to know is that the sleep need varies by age and condition. The sleep need, trivially, is the amount of sleep that a person needs to properly “recharge batteries” and wake up again without feeling tired. On average, newborns need 12 to 18 hours of sleep per day, adolescents about 9 hours and adults 7 to 9 hours per day. First consideration: Yes, we would all like to be newborns for the rest of our lives! Second consideration: the sleep need decreases with age and enormously varies among individuals, so there is no rule. What is sure is that sleep is cumulative: if at night we don’t sleep enough, the next day we’ll be fatigued and actually feel a sort of “sleep debt”.
Many hypotheses have been made to explain the functions of sleep, but it is still too hard to draw up an exhaustive list endorsed by scientific evidences. The second important thing to know is that our sleep follows some patterns known as sleep cycles. Without giving too many details (that you can find here), we sleep by cyclically alternating light and deep sleep phases. Intuitively, it is much easier to wake up during a light sleep period, better known as REM sleep phase, than during a deep sleep one. As it is depicted by the figure below, under normal conditions REM sleep phases recur on average every 90 minutes.
When we decide to take a nap, we should know that, if we are about to start the usual sleep cycle, after about 45 minutes we’ll be in the midst of the first deep sleep phase. In a sense, if we need to set the alarm, we should decide for either taking a short nap (20 to 30 minutes) or a long one (90 minutes), so as to wake up immediately after or before a light sleep phase. Unless you’re lucky enough to afford a nap of one hour and a half per day, you should probably take these considerations seriously 🙂
As this website explains, a power nap is a “sleep session that happens during the day (ideally between 1:00 to 4:00 PM) lasting between 10 and 30 minutes“. Power napping has been scientifically assessed as an effective way to relax, reduce fatigue, boost responsiveness and improve the mood. Apparently, a quick nap is even better than caffeine to improve both motor and learning skills.
Of course, napping can have negative effects as well. This webpage reports that “napping isn’t for everyone. Some people have trouble sleeping in places other than their own beds, while others simply can’t sleep during the day“. Right after the nap time, it may happen to feel disoriented and groggy… this is called sleep inertia. In other cases, a nap could interfere with night-time sleep and make us feel perfectly awake at 2:00 AM, thus leading to wonderful insomnia night sessions (that I wouldn’t wish even on my worst enemy).
Kind Yawns to You all.