When I woke up this morning my girlfriend asked me, “Did you sleep good?” I said “No, I made a few mistakes.”
Over the years, I’ve written about the topic of sleep because of its important role with both health and productivity. Some very “hot off the press” research findings related to both are worth noting.
Sleep and Health (or is it Health and Sleep?)
- At Sleep 2011, the 25th Anniversary Meeting of the Associated Professional Sleep Societies LLC (APSS), research was presented showing that people with a “normal” sleep duration of six to nine hours per night had higher self-reported scores for quality of life and lower scores for depression severity compared to short and long sleepers. A new study by the Centers for Disease Control and Prevention (CDC) links too little sleep (six hours or less) and too much sleep (10 or more hours) with chronic diseases — including coronary heart disease, diabetes, anxiety and obesity — in adults age 45 and older.
- Researchers from Wageningen University and the National Institute for Public Health and the Environment (RIVM) studied the association between the duration of sleep and cardiovascular disease among a group in 20,000 people. Those who slept less than 6 hours and who slept badly had 65 percent higher risk of heart disease compared to those who had 7-8 hours of good quality sleep (short sleepers who woke up feeling rested did not have the same CHD risk).
- Research by David Dinges, a sleep expert and head of the Sleep and Chronobiology Laboratory at the Hospital at University of Pennsylvania, found that sleep-deprived among us are lousy judges of our own sleep needs. In his study using a psychomotor vigilance task as a performance measure, he found that those who had eight hours of sleep hardly had any attention lapses and no cognitive declines over the 14 days of the study. However, participants in his study who slept for only four or six hours a night had results that declined steadily with almost each passing day (by the sixth day, 25 percent of the six-hour group was falling asleep at the computer during the study).
- Finally, in new research from 525 middle-aged people participating in the Morehouse-Emory Partnership to Eliminate Cardiovascular Health Disparities (META-Health) study, those who reported six or fewer hours of sleep had higher levels of three significantly higher inflammatory markers: fibrinogen, IL-6 and C-reactive protein which are independent risk factors for CHD and stroke.
What is the Optimum Nap Time?
My colleague, friend, and world recognized sleep expert Dr. Mark Rosekind (now on the U.S. National Safety and Transportation Board) conducted a study in 1994 that examined the effectiveness of a planned in-flight nap to maintain performance and alertness in long-haul flight operations in conjunction with NASA and the FAA.
One group of pilots was given an opportunity to take 40 minute naps mid-flight, and ended up getting an average of 26 minutes of actual sleep. Their median reaction time improved by 16 percent following their naps1.
Non-napping pilots, tested at a similar halfway point in the flight, experienced a 34 percent deterioration in reaction time. They also experienced 22 micro sleeps of 2-10 seconds during the last 30 minutes of the flight. The pilots who took naps experienced none.
Newer research even provides a snapshot of exactly how long naps should be to maximize altertness and performance2.
The research describes limiting subjects’ sleep to five hours overnight, then having them nap at 3pm for either 5 minutes, 10 minutes, 20 minutes or 30 minutes. For up to three hours after the nap they monitored the subjects with EEG and other assessments and found the following:
- 5 minute nap is essentially useless
- 10 minute nap showed immediate benefit and some benefit lasting 2 1/2 hours
- 20 minute nap needed about 35 minutes to show benefits some of which lasted a bit over 2 hours
- 30 minute nap impaired the subjects for a while (took a bit to wake up again) but had some benefits for about 2 1/2 hours
Well, time to consider just when I should take a nap today….Be well….
Check out Dr. Nowack’s book:
Clueless: Coaching People Who Just Don’t Get It
by by Sandra Mashihi Ph.D. and Kenneth Nowack Ph.D
Also try Dr. Nowack’s new free validated assessments (personality, resilience, and career strengths) at http://talenttools.org
- Rosekind, M.R., Graeber, R.C., Dinges, D.F., Connell, L.J., Rountree, M.S., and Gillen, K. Crew Factors in Flight Operations IX: Effects of Planned Cockpit Rest on Crew Performance and Alertness in Long-Haul Operations. (NASA Technical Memorandum 108839). NASA Ames Research Center, Moffett Field, CA, 1994.
- Brooks, L. (2006). A brief afternoon nap following nocturnal sleep restriction: which nap duration is most recuperative? Sleep, 29, 831-840.