Replenish Energy by Taking a Nap
Purpose: Napping may improve memory, physical performance, decision making, nighttime sleep, and stress levels.
Background
All known species in the animal kingdom sleep multiple times during the day. Research suggests that humans are naturally multiphasic and are internally programmed to sleep for one long period at night and a short period during the middle of the day. For this short period to be considered a nap, it must be more than five minutes and less than two sleep cycles (two sleep cycles is about three hours).
According to research from NASA, alertness may improve by as much as 100% and productivity by 13% following a nap. Napping may elevate mood and decrease feelings of irritability, depression, and anger that are associated with fatigue. Furthermore, napping may reduce cortisol levels (the body’s stress hormone), which may make it easier to fall asleep at night. A lead researcher on naps, Sara Mednick, PhD from the University of California, Irvine has created a Nap Wheel that may help people select a nap time and duration that optimizes the benefits of napping. The Nap Wheel is covered in the Practice section below.
Practice: This practice may help someone to replenish energy by taking a nap.
There are general rules for napping that are based on research. Understanding these rules may help someone to decide what time of day to take a nap and how long to nap for to achieve specific health outcomes.
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When to Nap
To benefit from napping, someone should wait at least two hours after waking from nighttime sleep to begin a nap and a nap should end no later than three hours before nighttime sleep begins. Peak napping benefits occur between 1pm and 3pm. Since napping occurs when body temperature is highest, napping after exercise may help someone fall asleep quicker (this is opposite for nighttime sleeping). The body’s internal clock will adapt to the nap time, so it is best to be consistent with the time of day that the nap occurs. Eating and drinking should be avoided up to three hours before a nap to avoid creating digestive troubles.
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How Long to Nap
Benefits from napping begin to occur after the first five minutes of the nap and peak at about the three hour mark, which is approximately two sleep cycles. After two sleep cycles, the nap may begin to disrupt internally programmed sleep patterns and interfere with nighttime sleep. The duration of the nap will determine what stages of the sleep cycle are achieved. Achieving stage 2 sleep may help improve alertness, slow-wave sleep may help repair the body, and REM sleep may help improve creativity and memory. The Nap Wheel created by Sara Mednick, PhD, and located at the end of this Practice section, can be used to determine the ideal nap time and duration. The Nap Wheel is designed for someone on a normal sleep schedule, so if someone is sleep deprived it may not be as accurate.
Nap Environment
The ideal nap environment should be dark, quiet, and safe. An eye mask and white noise machine can help create a dark and quiet environment. If a person chooses to nap when sitting, then the head and limbs should be supported to prevent “nap nod.” Set an alarm to wake up at the desired time. If possible, use a smartwatch alarm that can read the body’s electrical signals so that waking up occurs during a lighter sleep wave. Waking up during a lighter sleep wave may prevent a feeling of grogginess from occurring.
Nap Wheel
Use the interactive Nap Wheel, created by Sara Mednick, PhD, by clicking here. The Nap Wheel consists of:
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An outer rim representing the 24 hours in a day.
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A bright blue circle representing the amount of REM sleep that a person may receive depending on the hour of the day.
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A yellow circle representing the amount of slow-wave sleep that a person may receive. Slow-wave sleep increases according to the length of time that a person has been awake.
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A white inner portion representing Stage 2 sleep. Stage 2 sleep is a constant and will almost always make up the first 20 minutes of a nap.
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A “wake-up time” dial that can be adjusted to help plan the nap. Start by placing the dial on the hour that waking up occurred this morning. Then, decide how much stage 2, slow-wave, or REM sleep to receive from the nap. Look at the nap wheel and see where the yellow slow-wave sleep and blue REM areas match the desired amount.