The correlation between sleep and age in dogs (Canis lupus familiaris)

Abstract

Sleep is a fundamental behavioral and neurophysiological process that plays a critical role in the well-being of dogs (Canis lupus familiaris). As a species that shares its life closely with humans, the dog has become an increasingly valuable model for studying sleep physiology and its relationship with aging and neurodegenerative disease. This review provides a comprehensive overview of the changes in sleep patterns that occur across the different life stages of the dog, from the neonatal period to senescence. In neonates, sleep is dominated by REM activity, which supports synaptic pruning and early neural circuit development. During the juvenile phase, progressive maturation of sleep electrophysiology occurs, with full stabilization extending beyond 12 months of age. In adulthood, dogs exhibit a polyphasic sleep pattern characterized by distinct REM and NREM stages, sleep spindles subject to sexual dimorphism, and hemispheric asymmetry during sleep. With aging, sleep becomes increasingly fragmented, with a reduction in REM sleep and compensatory increases in daytime napping. These changes are particularly pronounced in dogs affected by Canine Cognitive Dysfunction, a neurodegenerative condition analogous to Alzheimer's disease in humans, in which impaired NREM sleep compromises glymphatic clearance of beta-amyloid and tau proteins. The growing availability of non-invasive polysomnographic techniques positions sleep assessment as a promising tool for the early detection and monitoring of age-related cognitive decline in veterinary practice.