Effects of hypocaloric diet on sleep in young and old rats.

Aging produces a loss in a number of behavioral and cognitive functions, including sleep. Hypocaloric diet is one of the few methods that have been shown to retard the effects due to age. However, the effects of such a diet on sleep have never been investigated. In the present study, 21 months old male F344 rats fed a 60% calorie-reduced diet continued to have a significant reduction in delta power (0.3-4 Hz EEG), less sleep following 12 h total sleep deprivation (TSD) and increased sensitivity to caffeine compared to young rats (3 months) fed a similar diet. These results indicate that caloric restriction is unable to prevent the decline in sleep that occurs with aging.