It is now clear that genetics plays a major role in sleep traits. Although environmental factors can influence sleep duration and intensity, certain genetic variants are known to affect these traits, and in some cases can even lead to familial sleep disorders.
Sleep is defined as a reversible natural state of unconsciousness in which there is a decreased responsiveness to external stimuli and relatively low activity.
Sufficient, high-quality sleep is essential for mental and physical well-being. The American Academy of Sleep Medicine recommends a daily sleep duration, in adults, of at least 7 hours per night on a regular basis.
Unlike other mammals, sleep duration in humans is thought to be regulated by two processes: the homeostatic S-process that increases during wakefulness and dissipates during sleep and the C-process, controlled by the circadian clock that is synchronized with the Earth's day-night cycles through the secretion of melatonin. In addition, sleep duration is a process that adjusts according to needs, so that when sleep is lost, compensatory mechanisms are activated that extend the duration of subsequent sleep.
Sleep is necessary for memory consolidation and involves the incorporation of memories acquired in the hippocampus into the neocortex brain network, where their long-term storage occurs.
Chronic sleep and circadian rhythm disturbances have been associated with an increased risk of mood disturbances, lower cognitive performance and cardiometabolic disturbances. Understanding the role of genetics and the underlying biological mechanisms that trigger sleep-associated disorders is still the subject of multiple studies.
13.5 million variants
Borbély AA, Daan S, Wirz-Justice A, Deboer T. The two-process model of sleep regulation: a reappraisal. J Sleep Res. 2016 Apr;25(2):131-43.
Dashti H.S., Jones S.E., et al. Genome-wide association study identifies genetic loci for self-reported habitual sleep duration supported by accelerometer-derived estimates. Nature Communications, 07 Mar 2019, 10(1):1100.