title: Exercise and sleep in aging: emphasis on serotonin.
abstract: Reductions in central serotonin activity with aging might be involved in sleep-related disorders in later life. Although the beneficial effects of aerobic exercise on sleep are not new, sleep represents a complex recurring state of unconsciousness involving many lines of transmitters which remains only partly clear despite intense ongoing research. It is known that serotonin released into diencephalon and cerebrum might play a key inhibitory role to help promote sleep, likely through an active inhibition of supraspinal neural networks. Several lines of evidence support the stimulatory effects of exercise on higher serotonergic pathways. Hence, exercise has proved to elicit acute elevations in forebrain serotonin concentrations, an effect that waned upon cessation of exercise. While adequate exercise training might lead to adaptations in higher serotonergic networks (desensitization of forebrain receptors), excessive training has been linked to serious brain serotonergic maladaptations accompanied by insomnia. Dietary supplementation of tryptophan (the only serotonin precursor) is known to stimulate serotonergic activity and promote sleep, whereas acute tryptophan depletion causes deleterious effects on sleep. Regarding sleep-wake regulation, exercise has proved to accelerate resynchronization of the biological clock to new light-dark cycles following imposition of phase shifts in laboratory animals. Noteworthy, the effect of increased serotonergic transmission on wake state appears to be biphasic, i.e. promote wake and thereafter drowsiness. Therefore, it might be possible that acute aerobic exercise would act on sleep by increasing activity of ascending brain serotonergic projections, though additional work is warranted to better understand the implication of serotonin in the exercise-sleep axis.
authors.affiliation: Research center on aging, Sherbrooke geriatric university institute-health and social services center, 1036, Belvedere South, J1H 4C4 Sherbrooke, QC, Canada; Department of kinanthropology, faculty of physical and sport education, university of Sherbrooke, 2500, boulevard de l'Université, J1K 2R1 Sherbrooke, QC, Canada.
authors.forename: M O
authors.initials: MO
authors.lastname: Melancon
authors.affiliation: Research center on aging, Sherbrooke geriatric university institute-health and social services center, 1036, Belvedere South, J1H 4C4 Sherbrooke, QC, Canada; Department of psychology, faculty of human sciences, university of Sherbrooke, 2500, boulevard de l'Université, J1K 2R1 Sherbrooke, QC, Canada. Electronic address: dominique.lorrain@usherbrooke.ca.
authors.forename: D
authors.initials: D
authors.lastname: Lorrain
authors.affiliation: Research center on aging, Sherbrooke geriatric university institute-health and social services center, 1036, Belvedere South, J1H 4C4 Sherbrooke, QC, Canada; Department of kinanthropology, faculty of physical and sport education, university of Sherbrooke, 2500, boulevard de l'Université, J1K 2R1 Sherbrooke, QC, Canada.
authors.forename: I J
authors.initials: IJ
authors.lastname: Dionne
mesh_terms: D000375:Aging / Q000502:physiology*; D000596:Amino Acids / Q000378:metabolism; D000818:Animals; D056352:Athletes; D015444:Exercise / Q000502:physiology*; D006801:Humans; D009415:Nerve Net / Q000502:physiology; D011301:Preoptic Area / Q000502:physiology; D011903:Raphe Nuclei / Q000502:physiology; D012154:Reticular Formation / Q000502:physiology; D059326:Serotonergic Neurons / Q000502:physiology; D012701:Serotonin / Q000172:deficiency / Q000502:physiology*; D012890:Sleep / Q000502:physiology*; D020178:Sleep Disorders, Circadian Rhythm / Q000503:physiopathology; D007319:Sleep Initiation and Maintenance Disorders / Q000503:physiopathology; D014364:Tryptophan / Q000378:metabolism / Q000627:therapeutic use; D014851:Wakefulness
chemical_list: D000596:Amino Acids; D012701:Serotonin; D014364:Tryptophan
keywords: 5-HT; 5-hydroxytryptamine; Acides aminés; Activité physique; Activité sérotonergique; Advancing age; Amino acids; CNS; Cerveau; Elderly; Locomotor activity; Neurotransmetteurs; Neurotransmitters; Personnes âgées; Physical activity; Prolonged exercise; SNC; Vieillissement