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How do you all deal with daytime sleepiness? Working or studying while drowsy is inefficient, leading to slow progress and many mistakes.
Here, I'd like to introduce the benefits of taking a power nap, following that desire for sleep (sleep pressure).
Vestiges of Evolution?
Monkeys, which have the closest DNA sequence to humans (Note 1), seem to take many naps. Humans generally stay awake for 14 to 16 continuous hours in their social lives, but humans report an afternoon dip (the phenomenon of feeling most sleepy around 2 p.m.), which may be a remnant of the primate evolutionary process. It can also be considered a genetically natural phenomenon to feel sleepy in the afternoon.
How to Take a Power Nap
If you're going to take a power nap, we recommend keeping it under 30 minutes. Long naps are not recommended.
Here's why.
In 2000, analysis by the National Center of Neurology and Psychiatry on "the habit of napping and the risk of dementia" revealed the following two points:
- People who nap for "less than 30 minutes" reduced their dementia incidence by approximately 1/7 compared to those with "no napping habit."
- People who nap for "1 hour or more" doubled their dementia incidence compared to those with "no napping habit."
In order of incidence rate, it was: "napping for 1 hour or more" > "no napping habit" >> "napping for less than 30 minutes." In other words, when you're sleepy during the day, it's better to nap than not to, but sleeping too much is worse than not sleeping at all.
If you sleep too much, you might experience sleep inertia (a state of grogginess where your mind doesn't work well for a while after waking up), or your sleep pressure might not build up enough at night, making it difficult to fall asleep. This can disrupt your sleep rhythm and lead to sleep debt. Therefore, it's important to be careful not to oversleep, even if you're sleepy.
Why is a Power Nap Good?
The above example introduced the effectiveness of taking a power nap when daytime sleepiness increases even with sufficient night sleep. Below, we will introduce the effectiveness of taking a power nap when staying up all night.
According to experimental results on the effects of staying awake for long periods and the benefits of napping, reaction times slow down when staying awake continuously for extended periods. Taking a 2-hour nap every 12 hours of continuous wakefulness (4 hours a day) reduced errors.
Even during short periods of sleep, rest and bodily repair occur, and it has recently been discovered that brain waste products can be removed during sleep.
Although daytime naps cannot reset sleep debt, even a short nap has been shown to significantly reduce errors, which is expected to lead to a reduction in industrial accidents.
When working late, instead of staying up all night, we recommend taking power naps between tasks, even if it means slightly reducing work time. In addition to reducing errors, it can help you concentrate better and work more efficiently.
However, in this case, sleep time is insufficient, and continuing this will accumulate sleep debt. Please incorporate this knowing that it is merely a symptomatic treatment.
【References】
*1: RIKEN, Press Release (2002), World's first genome map comparing humans and chimpanzees completed
