The efficacy of naps as a fatigue countermeasure: a meta-analytic integration.

Modern requirements for extended operations in aviation, transportation, the military, and industry have led to extensive research on countermeasures to mitigate the adverse effects of fatigue. The goals of this research were to (a) summarize and integrate existing research on naps as a fatigue countermeasure using meta-analysis, (b) identify the strength and significance of the effects of naps on performance and feelings of fatigue, and (c) identify factors that may moderate the effects of napping as a fatigue countermeasure. The results of these analyses can be used to predict nap efficacy as a function of length of the nap and the postnap interval. The results of these analyses also suggest an approach to work design that takes into account the optimal effects of naps as a fatigue countermeasure. Actual or potential applications of this research include the development of optimal work schedules to minimize fatigue and increase safety.