The current evidence that aging is associated with a significant increase in sleep-wake cycle complaints has individual, social, and economic consequences. These age-related changes occur as early as the middle years of life, with over 35% of the population in their forties to sixties reporting sleep difficulties. Age effects on non-rapid eye movement (NREM) sleep electroencephalogram (EEG) differ between brain topographical sites in parallel with age-related changes in gray matter density of the brain. A precise interaction between the homeostatic and circadian processes is required for optimal sleep and vigilance. Age-related increase in wakefulness during sleep may be associated with a phase angle change between the signal from the circadian clock and sleep-wake cycles. Age-related changes in the neural correlates of NREM sleep oscillations may also underlie changes in memory and brain plasticity. There is need to determine the consequences of age-dependent changes to the sleep-wake cycle in middle-aged individuals.