Battling Fatigue in Aviation: Recent Advancements in Research and Practice

Despite knowledge gained through decades of research, fatigue due to insuffi cient sleep remains an ingrained part of military and commercial aviation and represents a major threat to the health, safety, and effectiveness of aircrew. Long duty periods, high workloads, circadian disruptions, and insuffi cient recovery time between fl ights ensure sleepiness is a continued problem for both civilian and military aircrew. The majority of our knowledge concerning the effects of fatigue is gained from acute, total sleep deprivation laboratory-based studies which describe results in terms of the average individual’s response to total sleep loss. However, in operational environments, limited sleep over many days, termed chronic sleep restriction, is more commonly experienced than acute, total sleep deprivation, casting some doubt on the operational applicability of many previous studies. Furthermore, recent studies have identifi ed strong individual differences in fatigue resistance. Our understanding of the effects of chronic sleep restriction and the individual differences in response to fatigue is currently limited in comparison to that of acute sleep deprivation. In this review, we identify the substantial progress made over the last 2 decades in closing these gaps. Advances in understanding the effects of chronic sleep restriction, the recovery timeline associated with sleep loss, and individual responses to sleep loss represent a critical step in the improvement of current, and the formulation of future, countermeasures in the aviation environment. Adjustments to duty rotation and crew scheduling, refi nement of biomathematical models of fatigue, and application of currently available countermeasures are the most immediate of these improvements.