Peer-review started: August 22, 2016
First decision: October 21, 2016
Revised: November 10, 2016
Accepted: November 27, 2016
Article in press: November 29, 2016
Published online: March 28, 2017
Sleep is essential for maintaining normal physiological processes. It has been broadly divided into rapid eye movement sleep (REMS) and non-REMS (NREMS); one spends the least amount of time in REMS. Sleep (both NREMS and REMS) disturbance is associated with most altered states, disorders and pathological conditions. It is affected by factors within the body as well as the environment, which ultimately modulate lifestyle. Noradrenaline (NA) is one of the key molecules whose level increases upon sleep-loss, REMS-loss in particular and it induces several REMS-loss associated effects and symptoms. The locus coeruleus (LC)-NAergic neurons are primarily responsible for providing NA throughout the brain. As those neurons project to and receive inputs from across the brain, they are modulated by lifestyle changes, which include changes within the body as well as in the environment. We have reviewed the literature showing how various inputs from outside and within the body integrate at the LC neuronal level to modulate sleep (NREMS and REMS) and vice versa. We propose that these changes modulate NA levels in the brain, which in turn is responsible for acute as well as chronic psycho-somatic disorders and pathological conditions.
Core tip: Sleep is affected by many internal factors as well as lifestyle changes and vice versa. Noradrenaline (NA) is one of the molecules affected by lifestyle as well as sleep-loss; rapid eye movement sleep-loss in particular. Many of the sleep-loss associated cellular-molecular-behavioral and patho-physiological changes are induced by NA. Therefore, we propose that disciplined sleep habit, which would maintain optimum level of NA, is essential for leading healthy life.