Sleep is highly conserved across evolution, suggesting vital biological functions that are yet
to be fully understood. Animals and humans experiencing partial sleep restriction usually
exhibit detrimental physiological responses, while total and prolonged sleep loss could lead
to death. The perturbation of sleep homeostasis is usually accompanied by an increase in
hypothalamic–pituitary–adrenal (HPA) axis activity, leading to a rise in circulating levels of
stress hormones (eg cortisol in humans, corticosterone in rodents). Such hormones follow a …