When I lived in Italy, we went to school until 12:30 then returned home for 2 hours for lunch and a nap. Afterward we went back to study until 6:00. At the time I was astounded at how much more Italian high school students learned compared to American students. New research shows that the napping might have something to do with it.
A University of California, Berkeley study took 39 healthy adults and studied their ability to learn and memorize with or without naps. The participants who napped between learning sessions (for 90 minutes) improved their own scores by 10 percent while their non-napping counterparts saw scores dropping by 10 percent.
The two groups were given learning tasks that were intended to tax the hippocampus, a region of the brain that helps store fact-based memories. Both groups performed at comparable levels immediately after learning. Then one group was allowed to nap while the other was kept awake. At 6pm the two groups were given new information to learn, but the nappers were much better able to learn the new information than either those who stayed awake or even better than themselves in the morning.
“Sleep not only rights the wrong of prolonged wakefulness but, at a neurocognitive level, it moves you beyond where you were before you took a nap,” said study author and psychology professor Matthew Walker.
Other studies have indicated that sleep helps consolidate memories after cramming. Students who study then get a good night’s sleep remember more than those who stay up studying again, probably because the brain is able to make internal connections during sleep that link the learned information to other information stored in the brain.
In a similar study at the University of Haifa researchers found that midday naps allowed people to retain information better the next day, compared to non-nappers. They posit that sleep helped overcome interference — the brain processing new information that interferes with remembering old information learned earlier in the day. “This part of the study demonstrated, for the first time, that daytime sleep can shorten the time ‘how to’ memory becomes immune to interference and forgetting,” study co-author Avi Karni said in a statement. “Instead of 6 to 8 hours, the brain consolidated the memory during the 90 minute nap.” This also seems to confirm much older studies showing that students retain more information when they are given hourly breaks than when they go for two or three hours, but it also finds specific benefits to sleep during that break.
Is it just a matter of reducing our sleep deficit? We know that studies of the average sleep patterns of Americans done in the 1920s showed that the average American slept 9 hours, at a time when electricity was less widespread and there was no late night television or computers to distract us. Today the National Sleep Foundation‘s annual poll estimates that Americans get an average of about 6.7 hours of sleep during a weekday. We have not evolved in nearly a hundred years to need less sleep.
National Sleep Foundation poll
People sleeping less than 6 hours:
1998: 12 percent
2002: 15 percent
2009: 20 percent
People sleeping more than 8 hours:
1998: 35 percent
2002: 30 percent
2009: 28 percent
Dr. William Fishbein, a cognitive neuroscientist at CUNY did a similar study on relational learning, where the brain puts together facts learned separately to make new information. Students who did not speak Chinese were given two character terms in Chinese like sister or mother or maid which pictographically included a common radical. Then after either a break or 90 minute naps where slow wave (delta wave) sleep was monitored, the subjects were given multiple choice tests on novel Chinese words that included the female radical. Those with naps were more likely to choose words like “princess” instead of “ape”. Fishebein and his assistant Hiuyan Lau believe that the deep slow-wave sleep, even in the context of a power nap, helps people work out problems. Deep slow wave sleep generally happens before the REM dreaming stage and takes place with high amounts of delta waves in the brain.
Even 12 minute naps can boost some forms of memory, according to Dr. Robert Stickgold of Harvard Medical School. However a study in Detroit at the Henry Ford Hospital showed that sleep-deprived students had significantly higher alertness after napping, with a 60 minute nap being optimal. Longer naps were not helpful. Although the alertness levels were not strongly correlated with sleep stages, the slow wave sleep was again the most effective at adding alertness.
So the kind of sleep may be may be at least as important as the amount of sleep.
There are several things that you can do to encourage delta stage, slow wave sleep. Sleep with a blindfold or eliminate all lights from your bedroom (and bring a mask to school or work for naps). Keep your room warm or take a hot bath before bed then bundle up. Don’t eat late as digestion can interfere with deep sleep, even if you are tired after eating. Use white noise or earplugs if your partner snores. Or better yet listen to a CD that induces delta stage sleep.
Consider GABA which induces relaxation, analgesia, and sleep. Minerals which are no longer in the soil, hence are deficient in food are very important. Take sea vegetables, overnight infusions made with a full ounce of nettles, a dark sea salt or mountain salt, or supplements including magnesium, zinc, potassium, calcium and iron (but iron only if you need it.) B vitamins including folic acid can also prevent insomnia. Omega 3s from fish oil, which has DHA, can stimulate serotonin absorption by helping the cell membranes.
If you are being kept awake by mental chatter, passionflower is good, perhaps mixed with motherwort and blue vervain for anxiety. Or with motherwort and zizyphus seed (suan zao ren) for menopausal insomnia. Or with lavender and holy basil if you are too tired to go to sleep. Or zizyphus with polygala and reishi for insomnia with palpitations. Long cooked oyster shell and dragon bone (a kind of fossil used in Chinese medicine) can help settle your spirit.
Avoid benzodiazapenes like Valium, Ativan and Klonopin which reduce delta wave sleep, steroids, anti-osteoporosis medication like Evista, and even thyroid medications at night. SSRIs like Prozac can increase Delta sleep, but St. John’s wort or 5-HTP would be more natural substitutes.
Meditation rooms or nap rooms are starting to make their way into the workplace and it is worth alerting employers to the productivity benefits of napping. While this may require a paradigm shift from the adulation of the Type A employee who works 12 hour days and sleeps for 5 hours, it appears that better, more accurate work can be done by power nappers.
Students should cover the material, then take a nap before tests. And they should study before getting a good nights’ sleep. Remember, it isn’t just taking in information, it is making connections and organizing the information in your brain. And that requires deep, slow wave sleep.
Rabin, Roni Caryn. Behavior: Napping Can Prime the Brain for Learning. The New York Times. February 22, 2010. http://www.nytimes.com/2010/02/23/health/research/23beha.html?em
Aldridge, Susan, PhD. Taking midday naps may reduce death from heart disease. Health And Age. February 13, 2007. http://www.healthandage.com/professional/Taking-midday-naps-may-reduce-death-from-heart-disease
Mark Lumley et. al. The Alerting Effect of Naps in Sleep Deprived Subjects. http://www3.interscience.wiley.com/journal/119492492/abstract?CRETRY=1&SRETRY=0
Medline Plus. Afternoon Nap May Make You Smarter. http://www.nlm.nih.gov/medlineplus/news/fullstory_95553.html
Body Ecology. How taking Naps Can Improve Your Learning. http://bodyecology.com/archive/how-taking-naps-can-improve-your-learning.php
Why We Are Sleeping Less. CNN http://www.cnn.com/2009/HEALTH/03/04/sleep.stress.economy/index.html
Lauran Neergard. Napping Boosts Sophisticated Memory. http://www.huffingtonpost.com/2008/11/24/napping-boosts-sophistica_n_146193.html
- Lack of Sleep Affects Hormone Levels (mercola.com)
- Sleep on This: Nap Boosts Your Brain’s Ability to Learn (neatorama.com)
- Sleep and Learning: More sleep means less study needed (acupuncturebrooklyn.com)
- Dr. Michael J. Breus: One-Stop Shopping To Boost Your Memory: Take A Nap (huffingtonpost.com)