Should Students Take Naps?

Have a look at this infographic and see if you can be persuaded to take a nap- it’s not just good for students!

Click image to view PDF or read below.

Do you think you can fit naps into your daily life? Let me know why/not!

Actigraphic assessment of a nap – Review

Actigraphy device

This article describes the two techniques of measuring when a person is asleep: actigraphy and polysomnography.

KANADY, J. C., DRUMMOND, S. P. A. and MEDNICK, S. C. (2011), Actigraphic assessment of a polysomnographic-recorded nap: a validation study. Journal of Sleep Research, 20: 214–222. doi: 10.1111/j.1365-2869.2010.00858.x

Polysomnography (PSG) monitors many body functions including brain (EEG), eye movements (EOG), muscle activity or skeletal muscle activation (EMG) and heart rhythm (ECG) during sleep. After the identification of the sleep disorder sleep apnea in the 1970s, the breathing functions respiratory airflow and respiratory effort indicators were added along with peripheral pulse oximetry.

Actigraphy is done by a portable device usually worn around the wrist or ankle that registers movement. Actigraphy is much less cumbersome and invasive, and therefore more suitable to naturalistic and long term experiments.

The present study aims to determine if actigraphy can detect accurately sleep in healthy, young adults during a 90-min mid-afternoon nap opportunity when compared to PSG.

Conclusion:

actigraphy was fairly proficient in distinguishing the difference between a nap and a no-nap period of quiet rest. Although actigraphy overestimated sleep during the no-nap condition, the accuracy values remained reasonably high

Naps, Cognition, Performance – Review

This paper is one of the proceeds of a symposium held by the authors (“The Effect of Naps on Health and Cognition”, held at the 5th Congress of the World Federation of Sleep Research and Sleep Medicine Societies in Cairns, Australia, September 2007). It describes several research questions and nap-hypotheses, and an agenda for further research on naps is proposed.

Naps, cognition and performance. Gianluca Ficca, John Axelsson, Daniel J. Mollicone, Vincenzo Muto, Michael V. Vitiello. Sleep Medicine Reviews – August 2010 (Vol. 14, Issue 4, Pages 249-258, DOI: 10.1016/j.smrv.2009.09.005)

Practice points:

• examination of the interrelationships of napping, cognition and performance in four specific contexts
• the hypothesis that a split-sleep schedule provides more recovery than a single consolidated sleep period of the same total duration is examined. (Correctly timed split-sleep, shown to have positive effects, or at least no negative consequences on neurobehavioral performance, might be used for sleep-wake schedules in work environments that involve restricted nocturnal sleep due to critical task scheduling)
• the advantages and disadvantages of napping in the work environment are examined. (Napping is an effective important countermeasure to maintain adequate performance levels during extended work shifts, and in operational settings. Napping strategies should be a natural part of programmes having the aim to improve safety and health in the work place. / Short day-time naps are effective on vigilance and cognitive functions for subjects with moderately disturbed sleep and possibly for normal sleepers. Actually, a nap as short as 10 min can improve alertness and performance for about 2.5 h if prior sleep loss exists and for almost 4 h if preceded by normal sleep)
• benefits of napping for the learning of new material (Naps appear beneficial for memory consolidation of material newly acquired before the nap, either procedural or declarative. More robust effects seem to be given by slightly longer naps, about 60–90 min, possibly due to the build-up of both SWS and REM sleep)
• whether regular napping among older adults, particularly those in good health, may be beneficial to daytime wakefulness or detrimental to night-time sleep propensity. (The prevalence of spontaneous napping increases with age in adults. This increase is likely the result of increases in nighttime sleep disturbances, phase advance of circadian rhythms, co-morbid medical and psychiatric illnesses and poor sleep habits. / Frequent, unplanned, longer daytime naps in older adults have the potential to negatively impact nighttime sleep quality and may be associated with significant negative health consequences such as increased risk of morbidity, cardiovascular illness, falls and cognitive impairment. / Brief planned naps may be of benefit to the function of healthy older adults, and perhaps even older adults in poorer health)

Research agenda:

• How and to what extent the neurocognitive effects of naps may change as a function of their circadian placement should be explored in more details.
• Further studies are needed if we aim to understand the combinatory effects of several countermeasures to maximize alertness at crucial time points: for instance, it would be important to verify how the use of naps and caffeine are best combined in operational shift-work settings.
• It is still to be understood what sleep features are crucial for the “nap effect” on memory consolidation.
• Lab studies could seek the effects of naps on specific higher cognitive functions using ad-hoc paradigms and tasks.
• Research on naps and cognition should include the study of oneiric activity (i.e., dream features) during napping.
• The cognitive effects of napping at early ages should be explored, because this might be of interest with respect to learning processes and school performance.
• More elaborate self-report paralleled by objective assessment techniques, such as actigraphy, which allow for a better appreciation of the complexity of napping behavior, should be employed in large, representative samples of older adults which include both nappers and non-nappers.

Especially the second to last point is of interest to me. Would ‘younger children’ also include adolescents though?

Sleep Extension versus Nap or Coffee – Review

HORNE, J., ANDERSON, C. and PLATTEN, C. (2008), Sleep extension versus nap or coffee, within the context of ‘sleep debt’. Journal of Sleep Research, 17: 432–436. doi: 10.1111/j.1365-2869.2008.00680.x

An interesting article comparing three methods of reducing daytime sleepiness against a control group.

The setup was to test one countermeasure each week, in one test day a week, to see the effects of:

1. usual sleep (control group)
2. sleep extension (sleeping up to 90 minutes longer at night)
3. afternoon nap (20 minutes sleep within 30 minute period)
4. afternoon coffee (2 cups of coffee)

Rethinking Sleep – Review

From the New York Times: Rethinking sleep by David K. Randall

Mr. Randall states that we only started believing in 8-solid-hours-sleep in Western society, and only after the industrial revolution. Perhaps midday naps were unpopular to factory owners? There are other unhealthy sleeping habits connected to the industrialized world: think of shift work and night jobs.

But even today, in many societies naps are a way of life. In Spain, although in decline, people take a siesta after lunch, the main meal of the day. In China and other Asian countries, taking a powernap at your desk makes you seem motivated and effective, not lazy.

Further in the article, texts from historical records like Shakespeare are cited as proof that daytime sleeping was once common.

A character in the “Canterbury Tales,” for instance, decides to go back to bed after her “firste sleep.” A doctor in England wrote that the time between the “first sleep” and the “second sleep” was the best time for study and reflection.

Smart Sleep Literature Links

Following are links to literature I read on the topic of sleep, most recent on top. I will update this list as I go along, hopefully making this post a complete reference at the end of the semester (some articles are protected and can be read on the TU/e network only, sorry). As I go along, I will publish separate posts with reviews for each article and link to those as well.