Napping myths

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This text is part of: "Science of sleep" by Piotr Wozniak (2017)

Myth #1: Only lazy people take naps

In some cultures, this harmful myth makes people feel ashamed that they are weak enough to need a nap. This myth must be abolished promptly. Naps have a great effect on cognitive function and productivity. If you want to take a nap, take it and announce it proudly. You are doing a smart thing. Naps make you smarter!

When Newt Gingrich was caught asleep on camera, commentators pointed fingers in all wrong directions: he is getting old, he is tired of the campaign, he might be suffering from Alzheimer's, etc. Gingrich was set to video-stream live via satellite hook-up to the American Israel Public Affairs Committee. During a preceding Panetta speech, he opted for a quick nap in a sitting position. His age or health did not need to have to play any role here. In fact, Newt was doing a smart thing: he was clearing up his brain before appearing before a demanding audience. However, despite a short span of time available, he managed to launch deep sleep and woke up with clear signs of sleep inertia. He did not know where he was and what he was about to do! He recovered pretty fast with stump lines attacking radical Islam. Those sleep inertia symptoms did not need to indicate he was tired of the campaign or that his sleep deprivation carried over from many days of sleep debt. Even a single night of lost sleep would be enough to put anyone in his position. His being a political old-timer worked against him. No novice would be able to overcome the stress of public sleeping to get a few zzzs. The only obvious mistake Gingrich made was to fail to get his full load of sleep on the preceding night. For more see: Why naps cause sleep inertia?

Myth #2: A nap is a nap is a nap

This myth says that every nap is a good nap. It does not matter when it is taken and how long it lasts. This myth lives deep in the psyche of inexperienced nappers who often do not realize the myriad of genetic, metabolic, neural, and hormonal processes that cycle through the human body throughout the roughly 24 hour period. In the section titled Best nap timing, I include a general partitioning of the circadian cycle with a short analysis of what processes occur when a nap is taken at each selected point of the cycle. Naps taken at different points of the circadian cycles are as different as chalk from cheese. Some are refreshing. Some are a waste of time. Some may be unhealthy (or at least inefficient). Some will last several hours!

Myth #3: Make sure you wake up from Stage 2 NREM

Some napping "experts" will tell you to use an alarm clock to make sure you wake up after 15-20 min from Stage 2 NREM. Supposedly, longer naps send you into deep sleep (Stage 3/4 NREM), and you wake up groggy. In reality, it is the timing of naps in reference to the circadian cycle, as well as the prior sleep deprivation and REM-sleep deficit that will determine the nap duration and the effects of the nap. On some occasions, it may happen that a nap cut short with an alarm clock will be somewhat refreshing and will prevent the ripples of a wrongly timed prolonged nap. However, it is always better to choose the appropriate time for a nap. It will usually be around 7-8th hour of the subjective day. This translates to 7-8 hours from waking in free running sleep. However, in conditions of sleep deprivation, or misaligned sleep cycle, it is safer to take an earlier nap or even skip the nap entirely to help cycle re-synchronization.

Did you hear a story in which Einstein supposedly napped with a pencil to wake up as soon as the pencil dropped? I doubt a great genius would make this mistake on a regular basis. I am sure he had a chance to compare the values of a well-timed natural nap and an interrupted nap. Perhaps a pencil dropped indeed. Once? Perhaps the genius brain was thus deprived of some new creative insight? Or conversely he was inspired by an interrupted mentation? Perhaps it was just a nice story to tell over a cup of tea? Whatever the truth, do not follow this example! Let your brain decide how long the nap should last!

Myth #4: The circadian cycle can be ignored or abolished

A harmful myth says that we could ignore the circadian cycle, so that the sleep can be reduced to one-dimensional homeostatic process. This myth comes from the lack of understanding of the two-process nature of sleep. It made many to believe that polyphasic sleep is a good long-term lifestyle choice. The myth comes from the lack of appreciation of the overwhelming power of the primary circadian sleep component. Consequently, the myth bears a belief that naps can be induced at will at any time that is sufficiently far away from the prior nap.

Have a peek at the following amazing picture obtained with the help of SuperMemo.

Grades of a biphasic sleeper in relation to the circadian phase showing two major peaks in alertness and learning quality during the day

The graph shows the powerfully biphasic nature of the human circadian cycle. The horizontal axis shows the circadian time, i.e. the time that elapses from phase 0, i.e. the predicted "end of the night" time. The prediction comes from the circadian model employed in SleepChart, and is derived from the sleep log collected in SuperMemo. The red line is the predicted alertness derived from the same sleep log data using the two-process model of sleep developed for the purpose of sleep optimization in SuperMemo (the model is inspired by similar work of Alexander A. Borbely and Peter Achermann). The alertness is a resultant of the status of the two sleep-drive processes:

  1. the homeostatic process and
  2. the circadian process.

The blue dots are recall data taken from an actual learning process in SuperMemo. In other words: red is the model, blue is the data. Both tell the same story! For skeptics who do not believe in scientific models, blue-dot unprejudiced data should be the ultimate clinching argument. The graph says unequivocally that we got two major peaks of alertness during the day. It also states clearly that there are only two valleys conducive for sleep and napping.