LAUSR

Currently, millions of individuals work outside of the conventional 9-to-5 work shift and are often required to sleep at times that are not conducive to maximizing restorative sleep. This insufficient sleep leads to health and cognitive performance impairments that compromise workers’ safety and productivity. This can be mitigated by sleeping at the time of day that maximizes the restorative benefits of sleep and working at favorable hours, within their particular opportunity windows. Here, we present an optimization algorithm to identify sleep and work schedules that maximize alertness during work hours, while reducing impairment during non-working hours to the greatest extent possible. We developed an optimization algorithm that searches through a large number of possible sleep and work schedules to identify the one that maximizes alertness during work times, while meeting user-provided constraints, such as the periods during which the user has flexible opportunities to sleep and work. To generate the possible sleep and work schedules, we used the well-validated Unified Model of Performance (UMP), including its ability to predict sleep latency and sleep duration. To assess the algorithm, we simulated four experimental studies, where we compared the effectiveness of the sleep schedules obtained by the algorithm against those of the sleep schedules used in the studies. In addition, we tested the algorithm’s ability to simultaneously optimize sleep and work schedules in one of the studies. Using the same amount of sleep as in the studies, the algorithm proposed sleep schedules that optimally allocated sleep, reducing alertness impairment during work hours by an average of 29%. Similarly, by simultaneously optimizing sleep and work schedules during a recovery period following a chronic sleep-restriction challenge, the algorithm’s solutions resulted in recovery to baseline alertness levels two days earlier than the conventional 9-to-5 work schedule. Our work provides the first quantitative tool to optimize sleep and work schedules and complements other existing fatigue-management tools to provide a more comprehensive set of countermeasure strategies to mitigate alertness impairment due to limited sleep.