Adolescent sleep patterns in humans and laboratory animals

Abstract

One of the defining characteristics of adolescence in humans is a large shift in the timing and structure of sleep. Some of these changes are easily observable at the behavioral level, such as a shift in sleep patterns from a relatively morning to a relatively evening chronotype. However, there are equally large changes in the underlying architecture of sleep, including a > 60% decrease in slow brain wave activity, which may reflect cortical pruning. In this review we examine the developmental forces driving adolescent sleep patterns using a cross-species comparison. We find that behavioral and physiological sleep parameters change during adolescence in non-human mammalian species, ranging from primates to rodents, in a manner that is often hormone-dependent. However, the overt appearance of these changes is species-specific, with polyphasic sleepers, such as rodents, showing a phase-advance in sleep timing and consolidation of daily sleep/wake rhythms. Using the classic two-process model of sleep regulation, we demonstrate via a series of simulations that many of the species-specific characteristics of adolescent sleep patterns can be explained by a universal decrease in the build-up and dissipation of sleep pressure. Moreover, and counterintuitively, we find that these changes do not necessitate a large decrease in overall sleep need, fitting the adolescent sleep literature. We compare these results to our previous review detailing evidence for adolescent changes in the regulation of sleep by the circadian timekeeping system (Hagenauer and Lee, 2012), and suggest that both processes may be responsible for adolescent sleep patterns.

Sleep and school education

“…A seemingly minor modification has to do with the time of class onset. Adolescents, whose circadian rhythms are better adapted to afternoons [1,49], are handicapped for morning learning [29,101], in part due to sleep inertia [24,84] and to the substantial modifications in sleep patterns and hormonal regulation experienced by teenagers [28]. Phase delays in the circadian timing of sleep during adolescence can favor the accumulation of persisting sleep deficits if school starts too early.…”

Sources of intraspecific variation in sleep behaviour of wild great tits

“…Variation in sleep across the animal kingdom has been partly attributed to differences in geographical location, precocial versus altricial development, size (Elgar, Pagel, & Harvey, 1988, 1990 and internal state (Davis, Darrow, & Menaker, 1983;Hagenauer & Lee, 2013;Randler, 2011;Spruyt, Molfese, & Gozal, 2011), but it is unclear to what extent these relationships exist in the wild. We examined the contributions of exogenous (i.e.…”

Variations in the sleep–wake cycle from childhood to adulthood: chronobiological perspectives

“…[15][16][17][18][19] Measurable outputs of endogenous rhythms such as hormone secretion and body temperature undergo changes across development. Phase delays during adolescence are also displayed in several non-human mammal species, 20 indicating that the phenomenon is likely driven by some common feature of mammalian biology. There are several plausible theoretical explanations linking changes in endogenous rhythms with the sleep-wake changes seen across development.…”

“…According to the model, a decrease in the buildup of sleep pressure across the day and in its dissipation across the night predicts the observed delay in sleep-wake timing and shortening of duration. 20 The findings of Jenni et al 56 provide support for a slower buildup of sleep pressure based on changes in waking slow wave activity across adolescence; however, no changes were found in slow wave activity during sleep. Another theoretical model proposed by Phillips et al 57 integrates several parameters to represent influences of circadian and homeostatic processes on neuronal firing and resultant circadian preference.…”

“…More complex interactions between internal and external factors may also play a role, for example, changes in sensitivity of the internal pacemaker to light has been suggested as a possible mechanism for the phase delay in adolescence. 55 In conjunction with the chronobiological and pubertal maturation perspectives, a recent homeostasis model proposed by Hagenauer and Lee 20 provides another possible account of delays in sleep-wake timing and shortening of sleep length. According to the model, a decrease in the buildup of sleep pressure across the day and in its dissipation across the night predicts the observed delay in sleep-wake timing and shortening of duration.…”