One for the night owls

After reading some recent posts on Facebook and LinkedIn investigating the writing habits of academics, I have realized that many, like me, fit the definition of “night owls” (i.e., those who are more productive at evening/night and prefer sleeping during daytime). If you are one, you surely know the struggle: most societies function on a 9:00–17:00 schedule, and the world certainly does not revolve around our special needs. The thing is, sometimes having a different sleep pattern than what is considered “normal” can make you feel like something is wrong with you. Because this is outside my field of expertise, I had to go deeper into researching sleeping habits, circadian rhythms, and chronotypes, and what I learned is actually pretty interesting.

As we know, human behavioral and physiological processes follow an “inner clock” with a 24-h (circadian) periodicity according to the day-night cycle. It has been demonstrated that our cells live by an autoregulatory metabolic loop that is reset daily by a “master clock” located in the hypothalamus [1]. When daily rhythms do not follow the typical day-night pattern for extended periods of time, these can be deemed sleep disorders. This is a growing concern in modern societies, as the natural responses of our bodies to environmental conditions are increasingly disrupted by factors such as artificial light, room temperature control, and sedentary lifestyle. However, as reported in a paper by Zhang et al. [2], “there are four major types of chronic circadian rhythm sleep disorders that are all stubbornly resistant to enforced rest-activity schedules and thus likely to be intrinsic biological propensities with a genetic substrate: advanced sleep phase disorder, delayed sleep phase disorder, free-running sleep disorder, and irregular sleep-wake disorder.” Therefore, these would not be disorders but phenotypes, that is, the result of interaction between specific genetic makeups and environmental factors. Such particular phenotypes have been termed chronotypes, and night owls would fall in the second of the abovementioned four categories.

An extremely interesting article published by Samson et al. in 2017 [3] explains the possible evolutionary significance of the “night owl” chronotype. What these scientists did was to study the behavior of a tribe of hunter-gatherers living in Tanzania: they had each participant wearing a monitoring device called an actigraph, and they recorded the time each volunteer was asleep over an extended period of time. As a result, all individuals were simultaneously scored as asleep for only 0.002% of the time. This means that, for most of the time, there was at least one awake individual in the tribe.

This research supports the so-called “sentinel hypothesis.” Proposed by F. Snyder in 1966 [4], this theory surmises that humans, like other animals, would organize their tribes, groups or societies so as to always have sentinels watching over the sleep of others, to protect their peers from possible dangers posed by wild animals and human enemies. Sleep is indeed a condition of extreme vulnerability, and this appears to reflect also in our NREM and REM sleep cycles: short periods of awakening during the night would serve to rapidly scan the surroundings to ensure that no danger is in sight. According to these findings, it is fair to assume that we still have individuals who are more prone to being awake at night because they carry the genetic makeup of those who used to serve as sentinels.

Therefore, if you have ever felt broken or just wrong because you could never bring yourself to follow a “normal” wake-sleep cycle, it may be time to give yourself a break. You are prone to falling asleep late because your ancestors were protectors, not because you partied too hard in college and never recovered from the odd hours (well, maybe…). Now, no one says that you have to live by the predominant standards imposed by society. You may perhaps consider turning to a career that will allow you to embrace your natural lifestyle and live more peacefully. An academic career may be suitable if you manage to avoid teaching early morning classes. Working as a freelancer, for example in consultancy, would allow you to make your own schedule. Finally, there are plenty of jobs that function on shifts: working in hospitality, health care, or managing 24-h technical facilities, you will make your colleagues happy by always offering to take the late evening shift.

Are you ready to embrace your inner owl? Let us know in the comments!


Disclaimer: This article is meant to illustrate a non-pathological condition, i.e., a sleep behavior that is well tolerated by a person, with no significant consequences on their health and productivity. However, an irregular sleep pattern can be pathological and take a heavy toll on a person’s health, influencing their quality of sleep, productivity, and life in general. Insomnia can be the symptom of a disease or a disorder in itself. If you are bothered by insomnia, sleep irregularity, fatigue, confusion, forgetfulness, slow reflexes, intrusive thoughts, hallucinations, etc., please seek medical advice as soon as possible.

[1] Gerhart-Hines and Lazar. Endocrine Reviews, 2015, 36(3):289–304

[2] Zhang, et al. Advances in Genetics, 2011, 74:231–247

[3] Samson et al. Proceedings of the Royal Society B: Biological Sciences, 2017, 284(1858):20170967

[4] Snyder. American Journal of Psychiatry, 1966, 123:121–136

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