Numerous research studies have shown that naps can have positive benefits for our declarative, fact-based memory. One study showed that infants were better able to hold onto memories if they napped after learning. Another study showed that this memory enhancement was positively correlated with the number of sleep spindles produced during naps. Similarly, in middle school students, naps after class helped students to recall information days later.

Timely sleep facilitates declarative memory consolidation in infants. (2015). Proceedings of the National Academy of Sciences of the United States of America., 112(5), 1625-1629. Retrieved from https://search.proquest.com/docview/1803136049?accountid=14496

Kurdziel, L., Duclos, K., & Spencer, R. M. C. (2013). Sleep spindles in midday naps enhance learning in preschool children. PNAS Proceedings of the National Academy of Sciences of the United States of America, 110(43), 1-6. doi:http://dx.doi.org/10.1073/pnas.1306418110

Lemos, N., Weissheimer, J., & Ribeiro, S. (2014). Naps in school can enhance the duration of declarative memories learned by adolescents. Frontiers in Systems Neuroscience, 8, 6. doi:http://dx.doi.org/10.3389/fnsys.2014.00103

If you can’t fall asleep after 20 or 30 minutes or can’t fall back asleep after waking up in the middle of the night, it’s a good idea to get out of bed and do something calm and quiet (and that doesn’t involve technology). The longer you stay in bed awake, the more time your brain has to begin associating your bed with wakefulness.

Go back to bed when you start to feel sleepy again.

Edinger, J. D., Wohlgemuth, W. K., Radtke, R. A., Marsh, G. R., & Quillian, R. E. (2001). Cognitive Behavioral Therapy for Treatment of Chronic Primary Insomnia. Jama, 285(14), 1856-1864. doi:10.1001/jama.285.14.1856

The science is still out. The scientific sleep world still doesn’t fully understand the side effects of sleeping too much (i.e. hypersomnia). If there’s such a thing as too much wakefulness and not enough sleep, then perhaps there is such a thing as too much sleep and not enough wakefulness.

But, there is a name for that terrible, groggy feeling you experience after sleeping for 11 hours versus your normal 8 hours. That’s called the sleep hangover effect.

Vaze, K. M., & Sharma, V. K. (2013). On the adaptive significance of circadian clocks for their owners. Chronobiology International, 30(4), 413-433. doi:http://dx.doi.org/10.3109/07420528.2012.754457

This guy might be onto something.

Sleep improves the consolidation of procedural motor skill memory–whether that memory involves riding a bike or performing athletic activities. More specifically, research reveals that stage 2 NREM sleep toward the end of the night plays an essential role in improving motor procedural memories.

This guy might be napping to improve his motor skill performance. You never know.

Practice with sleep makes perfect (sleep dependent motor skill learning) .Walker, M.P., Brakefield, T., Morgan, A., Hobson, J.A., and Stickgold, R.Neuron. 2002; 35: 205–211

Maybe that statement is a bit of an exaggeration. But, it is true that your level of sleep deprivation could lead to a state of impairment that is equivalent to that of a legally drunk individual. In fact, on average, it takes about 20 consecutive hours of wakefulness for you to reach the point of being legally drunk. In other words, an individual with 20 hours of sleep deprivation experiences the same performance in terms of psychomotor vigilance tasks (PVTs or lapses or micro-sleeps) compared to his baseline performance as an individual who is legally drunk.

Dawson, D., & Reid, K. (1997). Fatigue, alcohol and performance impairment. Nature, 388(6639), 1-235. doi:http://dx.doi.org/10.1038/40775

Admittedly, a person who is sleeping does look a lot a person who is dead. After all, one of the behavioral hallmarks of sleeping is reduced muscle tone. This helps explain why people sleep in a sprawled out, horizontal position.

So, how can you tell that a person is sleeping and not dead? While both individuals are non-responsive (another behavioral indicator of sleep), this non-responsiveness is reversible for the sleeping individual. If you disturb that state of sleep, the individual will regain consciousness. Not so much for the dead guy.

Davis, H., Davis, P. A., Loomis, A. L., Harvey, E. N., & Hobart, G. (1937). Changes In Human Brain Potentials During The Onset Of Sleep. Science, 86(2237), 448-450. doi:10.1126/science.86.2237.448

Alcohol may be responsible for both the hangover and poor sleep. Although alcohol is a sedative, it’s a powerful disruptor of natural sleep. It fragments your sleep so that you wake up many more times throughout the night, which you don’t necessarily commit to memory. This is why an individual who has consumed copious amounts of alcohol may find that he had a rough night of sleep.

Smith, C., & Smith, D. (2003). Ingestion of ethanol just prior to sleep onset impairs memory for procedural but not declarative tasks. Sleep: Journal of Sleep and Sleep Disorders Research, 26(2), 185-191. Retrieved from https://search.proquest.com/docview/620083134?accountid=14496

We definitely do not recommend going out and having a drink when you’re running low on sleep! One study showed that being legally drunk with only 4 hours of sleep resulted in 30 off-road deviations compared to only 3.5 deviations for an individual who received the same amount of sleep but was completely sober and 5 deviations for an individual who received 8 hours of sleep but was legally drunk.

Roehrs, T., Beare, D., Zorick, F., & Roth, T. (1994). Sleepiness and ethanol effects on simulated driving. Alcoholism: Clinical and Experimental Research, 18(1), 154-158. doi:http://dx.doi.org/10.1111/j.1530-0277.1994.tb00896.x

There’s a name for this anxiety that you feel in the dark when you’re trying to fall asleep. It’s called sleep anxiety. You start ruminating and catastrophizing about the things you didn’t do the day before, what you need to do tomorrow, etc. Your heart seems to beat a little faster, and you can’t seem to get yourself to relax

Sleep anxiety is especially common among patients suffering from insomnia. These individuals have overactive brains (including overactive emotional centers) that make them more alert and more anxious.

Nofzinger, E. A., Buysse, D. J., Germain, A., Price, J. C., Miewald, J. M., & Kupfer, D. J. (2004). Functional neuroimaging evidence for hyperarousal in insomnia. The American Journal of Psychiatry, 161(11), 2126-2129. doi:http://dx.doi.org/10.1176/appi.ajp.161.11.2126

If you are sleep deprived, please reconsider driving home from work! Drowsy driving is responsible for more road-traffic accidents/deaths than drunk driving alone.

Using the number of micro-sleeps as the standard of measurement, a research study found that, after 10 consecutive days of 6 hours of sleep, you’re as dysfunctional as you would be if you pulled an all-nighter. The same is true after 5 to 6 nights of 4 hours of sleep. Even just 1 micro-sleep behind the wheel can mean the difference between life and death.

Van Dongen, Hans P. A., Maislin, G., Mullington, J. M., & Dinges, D. F. (2003). The cumulative cost of additional wakefulness: Dose-response effects on neurobehavioral functions and sleep physiology from chronic sleep restriction and total sleep deprivation. Sleep: Journal of Sleep and Sleep Disorders Research, 26(2), 117-126. Retrieved from https://search.proquest.com/docview/620082798?accountid=14496

Sleep inspires creativity! Paul McCartney from The Beatles discovered the tunes and lyrics to some of the band’s songs in his sleep. Mary Shelley wrote her best-selling novel thanks to a scary dream she experienced. Thomas Edison’s inventive mind benefited from his daytime naps.  

As if these anecdotes aren’t convincing enough, a recent study from the field of cognitive neuroscience revealed that there is such thing as “Sleep to gain insight!” According to this research, sleeping on a problem previously worked on can increase our insight and problem-solving capacity  by 3x compared to staying awake.

Wagner, U., Gais, S., Haider, H., Verleger, R., & Born, J. (2004). Sleep inspires insight. Nature, 427(6972), 352-355. doi:http://dx.doi.org/10.1038/nature02223

Shift work has been classified as a probable carcinogen by the World Health Organization. Essentially, because of the disruption to the sleep-wake cycle, these types of jobs can induce cancer. Also, shift work leads to an increase in work absences due to illness.

Medical residents are notorious for working long hours (up to 30 hours at a single time!). It makes sense why they are extremely sleep deprived. This sleep deprivation can produce negative consequences for patient care. 1 out of 5 medical residents will seriously harm a patient due to a fatigue-related error. 1 out of 20 medical residents will kill a patient due to tiredness. However, the Accreditation Council for Graduate Medical Education recently repealed a 2008 rule that prevented first-year medical residents from working more than 16 consecutive hours. Talk about “no one [giving] a damn about you.”

Merkus, S. L., Drongelen, A. V., Holte, K. A., Labriola, M., Lund, T., Mechelen, W. V., & Beek, A. J. (2012). The association between shift work and sick leave: a systematic review. Occupational and Environmental Medicine, 69(10), 701-712. doi:10.1136/oemed-2011-100488

Czeisler, C. A. (2004). Work hours and sleep in residency training. Sleep: Journal of Sleep and Sleep Disorders Research, 27(3), 371-372. Retrieved from https://search.proquest.com/docview/620470080?accountid=14496

From observations of the !Kung tribes, humans should be going to bed without setting an alarm! Alarm clocks are tools that enforce wake up time and prevent us from waking up naturally. What’s worst still is that the blaring sounds of alarm clocks have a stress impact on our hearts.

Alarm clocks started during the Industrial Revolution because factories required workers to arrive on time. The factory whistle became the first ever alarm to wake up employees and to announce the beginning of the work shift.

Therefore, with this enforced wake up time, modern humans are not sleeping the way we were designed.

Kaida, K., Ogawa, K., Hayashi, M., & Hori, T. (2005). Self-Awakening Prevents Acute Rise in Blood Pressure and Heart Rate at the Time of Awakening in Elderly People. Industrial Health, 43(1), 179-185. doi:10.2486/indhealth.43.179

That precious hour of sleep that you lost isn’t trivial!

If you compare medical records before and after Daylight Saving Time begins, you’ll see a 25% increase in heart attacks.

If you do the same thing when Daylight Saving Time ends, you’ll see a 21% decrease in heart attacks.

Čulić, V. (2013). Daylight saving time transitions and acute myocardial infarction. Chronobiology International, 30(5), 662-668. doi:http://dx.doi.org/10.3109/07420528.2013.775144

Our technological devices act as psychological anchors that promote sleep procrastination. As we are trying to fall asleep or can’t seem to fall asleep, we want to pull out our gadgets and watch some Netflix or YouTube videos until we get tired.

However, the blue light from our screens blocks melatonin, which is a hormone released and used by the suprachiasmatic nucleus (SCN) to communicate to the rest of the body that it is nighttime and time to sleep. Consequently, pulling out those screens actually makes it harder to fall asleep.

Instead, millennials should shut down their electronics 45 minutes or so before bed.

Kroese FM, De Ridder DTD, Evers C and Adriaanse MA (2014) Bedtime procrastination: introducing a new area of procrastination. Front. Psychol. 5:611. doi: 10.3389/fpsyg.2014.00611

West, K. E., Jablonski, M. R., Warfield, B., Cecil, K. S., James, M., Ayers, M. A., . . . Brainard, G. C. (2010). Blue light from light-emitting diodes elicits a dose-dependent suppression of melatonin in humans. Journal of Applied Physiology, 110(3), 619-626. doi:10.1152/japplphysiol.01413.2009

Beresford, I.J., Hagan, R.M., Starkey, S.J., & Walker, M.P. (1995). Modulation of the rat suprachiasmatic circadian clock by melatonin in vitro. Neuroreport, 6 14, 1947-51.