Abstract

Sleep is a form of rejuvenation, which can be treated as a source of energy. This energy is available in limited quantities and individuals must decide when it should be renewed and when it should be consumed. Sleeping involves investing in energy and alertness but also a sacrifice of time. We derive and solve the inter-temporal utility-maximization problem on the length of sleep to obtain optimality conditions for the length of sleep. Several applications emerge from the analysis. These include the effects of labor-market opportunities on sleep patterns; the effect of having children; the consequences of decreased division of labor within the household; and the relationship between sleep deprivation and obesity. When data allows, those outcomes are tested using panel data from Iceland. The empirical results are consistent with the predictions of the theoretical model