It’s Okay to Sleep Late

Social Jet Lag and the Stigma of Being a Night Owl

The time that we naturally wake up and go to bed is determined by our individual body clock. If one had a body clock of exactly 24 hours, he or she would be perfectly prepared to meet the demands of society. However, people vary equally on both sides of this parameter. Yet, those who rise early seem to be admired by society, and those who rise late are subject to blame. People need to recognize the genetic nature of our circadian rhythms and abandon prejudice against “night owls.”

Circadian Rhythms and Chronotypes Influence Late Sleepers

An article published as a resource by the Division of Sleep Medicine at Harvard Medical School, “Individual Variation and the Genetics of Sleep At a Glance,” (last reviewed 12/18/07), explains that variations in our body clocks, called circadian rhythms, determine whether people are late or early risers. The variations in circadian rhythms are called chronotypes.

Circadian Rhythms are Determined by Genetics – Late Sleepers are Not at Fault

According to The Harvard study, one’s genetic make up determines the speed of the individual’s biological clock. Mutations in genes often cause differences between the biological clocks of parents and children.

Basically, if the genetic body clock runs faster than average (24 hours), an individual rises early and is referred to as a “morning person.” In sleep studies these chronotypes are referred to as a “lark.” If the clock runs slower than average, the term for a late sleeper is an “owl, and the individual’s internal clock tells him or her to sleep later.

Equal Numbers of Morning Persons and Late Sleepers

An article that appeared in Chronobiology International, Wittmann M et. al., 2006;23(1-2), states that, although there appears to be an average of 24 hours in the human biological clock, different chronotypes are spread evenly between early and late risers. Average persons, comprising 60 – 70% of individuals fall closely within the 24-hour cycle. The remaining 15 – 20%, who have abnormally rapid or slow chronotypes, are also equally spread in the opposite ends of the sleep spectrum.

Sleeping Late Can be Caused by Sleep Debt

The demands of work, school, children and social life disregard circadian rhythms and chronotypes. The late sleeper with a day job must rise early. It is the late sleeper who suffers the greatest difference between biological chronotype and social obligations, as schedules tend to favor early risers. According to Wittmann et. al., the owls tend to build up what is called a “sleep debt,” and try to catch up on sleep on days when they have no social obligations.

Social Implications for Individuals Who are Late Sleepers

People often boast of being “morning persons” while few admi they are night owls. Our society tends to associate early risers with a good work ethic and success, while viewing late sleepers as lazy or without ambition. Even sleeping late on the weekend is frowned upon. Late sleepers are often considered to be negative or even depressed.

Late Sleepers are Not Depressed

According to the article, “Sleep Disorders: Sleep and Depression,” published by Stanford University School of Medicine, November 20, 2009, only 15% of depressed persons oversleep, while the vast majority of clinically depressed persons suffer from inability to sleep. This would dismiss the prejudice that late sleepers are probably depressed persons.

Negative Association with Late Sleeping and “Self Help”

Nevertheless, the stigma associated with late sleepers remains widely accepted in the United States, perhaps due to a rigid work ethic. Many self-help books begin with the message to rise early. In actuality, when persons rise before the time determined by their biological clock, they are fighting their own circadian rhythm and their performance level may actually drop.

“Social Jet Lag” Affects Morning Persons and Late Sleepers Equally

Wittmann M, et. al., describe the difference between individual chronotypes and the demands of society as “social jet lag.” Late sleepers seem to be the most adversely affected by social jet lag, both biologically and socially. However, the early riser who is fighting his natural chronotype in order to appear “successful,” may actually suffer greater “social jet lag.”

Accepting Circadian Rhythms: Sleeping Late is Okay

It is time to abandon our prejudice against those who desperately need a cup of coffee in the morning in favor of those who jump out bed singing. Individual sleep habits are based on genetically determined biological clocks. Both early risers and late sleepers suffer “social jet lag” more or less equally.