Teenage Circadian Rhythm

The stereotypical teenage late nights and lazy morning are often attributed to bad habits or a youthful quest to be cool. Particularly lately, with the emergence of always-available social media, teenagers stay up into early morning hours maintaining their online presence. Many parents think that these ‘late night’ and ‘sleeping in’ habits are simply habits.

In fact, research shows that teenage and adolescent sleep patterns are hormonally influenced, and not behavioral quirks, rebellious statements or decided attempts to fit in socially. In the teenage years, the hormonal response to the 24-hour daily light/dark exposure that influences circadian rhythm is altered, making adolescents physiologically yearn to stay awake later at night and to remain asleep later in the day. 

The role of melatonin in sleep 

Melatonin is the naturally occurring hormone that is cyclically released in anticipation of darkness and is credited with preparing humans to sleep. In general, melatonin release follows approximately a 24-hour daily cycle, ideally eliciting consistent sleep patterns from day to day. 

In fact, manipulating the body’s melatonin levels can effectively alter a person’s sleep schedule. Synthetic melatonin has become popular as an over-the-counter sleep inducer in situations such as the sleeplessness characteristic of jet lag. Ingestion of the product at bedtime is reported to stimulate sleep, with the goal of attaining a restful sleep period corresponding to the adopted time zone. 

Adolescents and melatonin 

In turns out that adolescents have a delayed release of regular daily melatonin, which causes them to become sleepy later at night, hours after nightfall. Given the fact that teenagers have an established need for 8-10 hours of sleep per night, the delayed melatonin release that allows teenagers to fall asleep late in the day has the expected effect of predisposing them to remain asleep for longer into the late morning or early afternoon, when it is feasible.

In general, light exposure suppresses melatonin in humans, and thus the melatonin level of teenagers is expected to be suppressed in response to light. An experiment published in the Journal of Clinical Endocrinology and Metabolism measured the melatonin levels of teenagers in relation to light exposure. A pre pubertal group and a post pubertal group of subjects were examined and compared. The pre pubertal group experienced substantially greater melatonin suppression in response to light stimuli when compared to the post pubertal group. The study authors concluded that increased sensitivity to light might be a factor in delaying nighttime sleep in adolescents. 

It would seem that in an ideal world, teenagers should be able to get enough sleep. However, the early morning school start times and even earlier sports practice schedules force most teenagers to rise at early morning hours. Avoiding too much light in the evening hours may be a reasonable method of preventing melatonin suppression and the resulting delay in melatonin release. 

Would you recommend using oral melatonin as a method of correcting teenage sleep patterns?

References:

Crowley SJ, et al. Increased sensitivity of the circadian system to light in early/mid-puberty. J Clin Endocrinol Metab. 2015 Nov;100(11):4067-4073.

Hagenauer MH, et al. Adolescent changes in the homeostatic and circadian regulation of sleep. Dev Neurosci. 2009;31(4):276-284.