So you finally decided not to go to Parizod’s last night. You didn’t have to pull an all-nighter doing a Writing 20 paper
and it was your night off from the tenting shift. You actually got a good night’s sleep for once! What should you do
this afternoon? Take a nap anyway! Even after a full night’s rest it is common to experience sleepiness in the afternoon
known as the “Post-lunch dip”, but a study shows that a short nap can be the answer to this problem. The effects of a 20 minute Nap in the mid-afternoon on Mood, Performance, and EEG Activity by Mitsuo Hayashi,
Makiko Watanabe and Tadao Hori (1999) shows that a 20 minute afternoon nap can counter the effects of the “Post-lunch
dip.” Brief napping improves performance and self-confidence in mental tests and increases wakefulness for the rest
of the day as compared to a day without a nap.
In the study, seven healthy college students
slept between 6 and 8 hours at night and then took a 20 minute nap at 2:00 PM. The sleepiness of the students was measured
quantitatively with an EEG (Electroencephalogram)—a machine that measures the frequency and amplitude of electrical
signals in the brain—and qualitatively by a personal report given by each student. Both types of measurements concluded
that the students were in a more wakeful state for the rest of the day after the nap. The students were also tested on logical
reasoning skills and their ability to quickly identify a correct sound and symbol. Each of the scores greatly improved post
nap and the scores remained higher for the rest of the afternoon and evening as compared to a day without a nap. Perhaps most
importantly, each student reported much more confidence in their test results after napping.
Self confidence can be a major factor in academic
evaluations. Higher confidence along with less sleepiness and sharper logic, visual, and auditory skills could really pay
off in an afternoon exam or presentation. Moreover, since enhanced wakefulness, reasoning ability, and recognition skills
last for the whole day there are even more potential payoffs in the evening. The nap will help keep you from nodding off at
the Dillo when reading your history textbook and get you through your chemistry lab more efficiently at a late night in Perkins.
But if 20 minute naps are good, then would not
a two hour nap be even better? Not necessarily. The scientists purposefully ended the naps after 20 minutes to ensure that
the students were in a state know as “stage two” sleep when they woke up. Of the four possible sleep stages, stage
two is the time when the regenerative process takes place that leads to improved mental skills and gets rid of the “Post-lunch
dip.” In stage two, brain waves have slightly lower frequency and greater amplitude than when awake. After about 30-40
minutes, however, stage two ends and the brain waves become much greater in amplitude and even lower in frequency as the sleeper
enter stages three and four—the Slow Wave Sleep (SWS) stages. Although these slower waves are necessary at night since
they help the brain fully rejuvenate, they might have an adverse affect in the afternoon. Someone awakened from SWS will experience
a phenomenon known as “sleep inertia” which is that groggy, tired feeling someone has in the morning when functioning
on just a few hours of rest. Sleep inertia occurs because it is hard for the body to shake off the slow waves once they get
going and fully return to a waking state. As a result, the sleeper feels tired for a longer period. You do not want slow waves
running through your brain before a test because your brain will be sluggish for some time after waking. Arising from stage
two is best because you will get the restful benefits or your nap, but you won’t have to worry about ridding your brain
of those slow waves.
So spend some quality time with your pillow and
take a quick 20 minute afternoon nap even if you got to bed at a reasonable hour. Go to your dorm, the gardens, a couch in
the BC, or anywhere there’s a nice spot to lie down for a while. You can get rid of the sinking spell that happens after
lunch and your brain will function better for the rest of your day. But don’t forget to set your alarm . . . 20 minutes
is all you need!
Works Cited
Hayashi, Mitsuo,
Makiko Watanabe and Tadao Hori. “The effects of a 20 min nap in the
mid-afternoon
on mood, performance and EEG activity.” Clinical Neurophysiology 110.2 (1999):
272-279. Science Direct. Duke U Lib., Durham. 17 November 2003. http://www.sciencedirect.com/science?_ob=ArticleURL&_udi=B6VNP-3W1YHKV-&_coverDate=02%2F01%2F1999&_alid=128533261&_rdoc=1&_fmt=&_orig=search&_qd=1&_cdi=6184&_sort=d&view=c&_acct=C000004358&_version=1&_urlVersion=0&_userid=38557&md5=84c51742ebdb70a9f9ee0f4955e8d12d
Further Reading
Hobson, J. Allen.
Sleep. New York: Scientific American Library, 1989.