The Disputable Costs of Sleeping

Abstract

[eng] Simple summary: Many authors have claimed that sleep reduces the time spent on foraging, defense, and antipredatory activities. Therefore, sleep must provide some compensatory advantage. Instead, we show that sleep-related reductions in food intake and reproductive activities may in fact be beneficial, both for the individual and the species. Furthermore, we demonstrate that optimal prey are immature, weak, diseased, and senescent animals, and rarely sleeping individuals. Indeed, the reduction in sleep time observed in prey animals is not due to antipredation evolutionary pressure, but primarily to the need for time to eat and digest the high cellulose content of the herbivore diet, a set of tasks that leaves less time for sleep. In short, no animal restricts its life activities to sleep, meaning that the need for sleep ranks low on the list of life activities. In fact, sleep basically consists of doing nothing, and no living being can die from insomnia. Instead, the important thing is to maintain a state of effective wakefulness, which can only be achieved after getting enough sleep.