Power Naps Help Your Hippocampus Consolidate Memories

Power naps and your hippocampus work as a dynamic duo to consolidate memories.

Posted Apr 21, 2015

Wavebreakmedia/Shutterstok
Source: Wavebreakmedia/Shutterstok

Martha Stewart once said, “I catnap now and then, but I think while I nap, so it's not a waste of time.” Stewart is not alone. Rumi summed up the power nap in a similar way saying, "Though we seem to be sleeping, there is an inner wakefulness that directs the dreams, and that will eventually startle us back to the truth of who we are." 

Your brain is never really at rest. When you sleep deeply through the night or take a power nap—your brain is always at work. Neuropsychologists in Germany recently discovered that a power nap can improve retention of learned material five-fold

The April 2015 study, "Nap Sleep Preserves Associative but Not Item Memory Performance,” was published in the journal Neurobiology of Learning and Memory

Previous studies have shown that sleep improves memory performance. The new study focuses on the hippocampus and how different components of sleep—such as “sleep spindles” and slow-wave sleep (SWS)—play an important role in memory consolidation.

The researchers found that a power nap lasting 45 to 60 minutes produces a five-fold improvement of information retrieval from memory. More specifically, the researchers at Saarland University in Germany found that power naps dramatically boost the retention of hippocampus-dependent associative memories. 

The hippocampus (Greek for "sea monster") was given its name because it's shaped like a seahorse. The hippocampus plays an important role in the consolidation of information from short-term memory to long-term memory and in spatial navigation.

What Makes Power Naps So Powerful?

The researchers examined a particular type of brain activity—known as "sleep spindles"—which play an important role in memory consolidation during sleep. A sleep spindle is a short burst of rapid oscillations on the electroencephalogram (EEG).

The researchers believe that memory content—particularly information that was subconsciously tagged as being of high importance—is itemized and given priority during memory consolidation while you're in the sleep spindle phase of a power nap.

During a power nap, recently learned information is given a label, making it easier to recall that information at a later time. Power naps make your memory of something stronger, which is reflected by a greater number of sleep spindles seen on the EEG. 

The research team at Saarland University draws a clear conclusion from its study:

A short nap at the office or in school is enough to significantly improve learning success. Wherever people are in a learning environment, we should think seriously about the positive effects of sleep. A concentrated period of learning followed by a short relaxing sleep seems to be the winning formula for consolidating memories. 

How Much Sleep Should You Get in a 24-Hour Period? It Depends on Your Age.

Pixabay/Free Image
Source: Pixabay/Free Image

The only backlash of taking a power nap that I've experienced is that napping can throw off my circadian rhythms in a way that makes sleeping through the night less likely. I used to feel guilty about taking power naps . . . and then I read a Psychology Today blog post, “Nightly 8-Hour Sleep Isn't a Rule. It's a Myth,“ by Ray Williams.

In his blog post, Williams traces the evolution of human sleep patterns. He describes that we've evolved with two different types of sleep patterns: "monophasic" sleep, which consists of around eight hours of continuous nightly rest, and “polyphasic” sleep, which consists of sleeping in multiple short blocks throughout the day.

Throughout history, there have been some famous polyphasic sleepers, such as: Leonardo da Vinci, Thomas Edison, Nikola Tesla, Buckminster Fuller, and Margaret Thatcher. With hindsight, I realize that after my father retired, he became a polyphasic sleeper and it fueled his creativity. The older I get, the more polyphasic my sleep becomes. Would you consider yourself a polyphasic or monsophasic sleeper?

Regardless of when you get your sleep, another study from February 2015 by the National Sleep Foundation (NSF) provides updated guidelines for how much sleep human beings require at different stages of life.

The new recommendations for appropriate sleep duration include wider appropriate sleep ranges for most age groups. Below is a summary of the new 2015 NSF sleep recommendations for each day:

  • Newborns (0-3 months): Sleep range narrowed to 14-17 hours each day (previously it was 12-18)
  • Infants (4-11 months): Sleep range widened two hours to 12-15 hours (previously it was 14-15)
  • Toddlers (1-2 years): Sleep range widened by one hour to 11-14 hours (previously it was 12-14)
  • Preschoolers (3-5): Sleep range widened by one hour to 10-13 hours (previously it was 11-13)
  • School age children (6-13): Sleep range widened by one hour to 9-11 hours (previously it was 10-11)
  • Teenagers (14-17): Sleep range widened by one hour to 8-10 hours (previously it was 8.5-9.5)
  • Younger adults (18-25): Sleep range is 7-9 hours (new age category)
  • Adults (26-64): Sleep range did not change and remains 7-9 hours
  • Older adults (65+): Sleep range is 7-8 hours (new age category)

"This is the first time that any professional organization has developed age-specific recommended sleep durations based on a rigorous, systematic review of the world scientific literature relating sleep duration to health, performance and safety," Charles A. Czeisler, PhD, MD, chief of sleep and circadian disorders at Brigham and Women's Hospital at the Harvard Medical School, said in a press release. 

Conclusion: Power Naps Can Help You Seize the Day at Any Age

We all know from life experience that power naps make us feel good and are rejuvenating. Regardless of the benefits of sleep linked to the hippocampus and memory consolidation, taking a power nap can regenerate your body and brain. Taking a nap can kick-start the second part of your day.

Do you ever take power naps? If you can orchestrate your daily routine to include a power nap, it will help your hippocampus consolidate memories while giving you a psychological boost to seize the day throughout your lifespan.

If you'd like to read more on this topic, check out my Psychology Today blog posts:

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