How Do Naps Affect Sleep at Night? Napping Health Benefits and Harms

Sleep During the Day May Relieve Sleep Deprivation, Lead to Insomnia

A nap affects sleep by relieving sleep deprivation, but may cause insomnia
A nap affects sleep by relieving sleep deprivation, but may cause insomnia. Getty Images

It can be a delicate topic, one that may provoke unnecessary angst or even guilt: naps. A nap can be a wonderful indulgence, a daily plague, or a source of anxiety about how it might affect your night’s sleep. In general, how do naps affect sleep at night? What are the potential health benefits of napping to relieve sleep deprivation? Why might naps be harmful and worsen insomnia? Learn about the relationship between naps and nighttime sleep and whether they are something you need to avoid.

The Timing of Naps and Sleep Needs

Within 24 hours, a nap is understood to be a shorter episode of sleep that occurs apart from the longest period of overnight sleep. Most people sleep for about 8 hours during the night. Naps may be relatively brief, lasting only minutes, or may even be prolonged over hours. The strongest desire for daytime sleep in adults occurs in the mid-afternoon, typically between 1 and 3 PM. Why does this timing occur?

Sleepiness in the afternoon may be enhanced due to a natural lull in the alerting system of the circadian rhythm. Throughout wakefulness, this system counteracts the building sleepiness associated with the accumulation of a chemical called adenosine. The longer you stay awake, the sleepier you become; a concept called sleep drive. In order to balance this, the circadian rhythm works to keep you awake and alert. However, the alerting signal may not be quite strong enough in mid-afternoon to overcome the building sleepiness during this time.

For many, this results in a tendency or desire to take a nap. Shortly thereafter, the circadian signal strengthens and the sleepiness abates until bedtime.

The desire to take a nap in the afternoon may be stronger among those who are sleep deprived, getting less sleep than is needed to feel adequately rested.

Most adults' sleep needs are 7-9 hours of sleep nightly to feel rested. Excessive daytime sleepiness is the most common symptom of sleep deprivation. The desire to nap may also be more pronounced among people with poor sleep quality due to untreated sleep disorders, like sleep apnea and narcolepsy. Excessive sleepiness and napping may be a sign of a sleep disorder.

Children frequently require naps during the day up until the age of 4 or 5. Adults may indulge the sleepiness they experience in the afternoon and resume taking naps, if their schedule allows and more often in retirement

In general, people with a tendency towards insomnia may have difficulty falling asleep during a nap. They report they “can’t nap”. Insomniacs may describe themselves as being tired, but wired. The increased arousal signal that keeps insomniacs awake at night also keeps them from falling asleep during the day.

How Naps Can Undermine Sleep

There are many people who can take a nap without unwanted effects. This is especially true if you are not getting enough sleep at night to meet your sleep needs.

These naps may help you to catch up from inadequate sleep, relieve sleepiness, and avoid the health effects of sleep deprivation. Those with other sleep disorders may similarly be able to sleep more in the day without any difficulty falling or staying asleep at night. However, sleep during the day can affect sleep at night for some.

Naps that are more prolonged or that occur close to your intended bedtime can compromise your ability to fall or stay asleep at night. This resulting insomnia is due to a diminished sleep drive. As above, by staying awake for a longer period, the desire for sleep builds with increasing adenosine levels. However, sleep can clear away the adenosine and other neurotransmitters that cause sleepiness. As a result, after sleep, sleepiness is lessened.

If you take a nap in the afternoon, it is a little like hitting reset on the timer that controls your ability to return to sleep. A short nap, typically 15 to 20 minutes, will affect you less than a nap that lasts for hours. In addition, a nap in the early afternoon may allow you 10 hours in which to build up the desire for sleep again. However, a nap in the hours preceding bedtime may make it more difficult to get back to sleep later. Moreover, if you require 8 hours of sleep to feel rested and you sleep for 2 hours in the afternoon or evening, you may get less sleep overnight because your body may not require the additional sleep. Sleep will become more fragmented with more frequent awakenings and prolonged periods awake in the night.

For those who find their nighttime sleep becomes more difficult after naps, these should be minimized. If you find that you require frequent or prolonged naps, you may consider whether you are getting enough sleep at night. If you are getting sufficient hours, but the sleep is still not restorative, you should speak with a sleep specialist about the disorders that can undermine the quality of your sleep.

Naps can be wonderful, but if you suffer from insomnia at night as a result, they may be something to avoid.

Continue Reading