The impact of anticipating a stressful task on sleep inertia when on-call

Sleep inertia, the state of reduced alertness upon waking, can negatively impact on-call workers. The impact of anticipating a stressful task on sleep inertia, while on-call was investigated. Young, healthy male participants (n=23) spent an adaptation, control and two counterbalanced on-call nights in a sleep laboratory. On on-call nights participants were told they would either perform a speech or read quietly after waking. Participants were not woken during the night and were given an 8-h sleep opportunity (2300-0700) each night. Upon waking, sleep inertia was measured at 5, 15-min intervals using the Karolinska Sleepiness Scale, a Psychomotor Vigilance Task and a Spatial Configuration Task. Participants slept, on average, 7.5h in all conditions. Participants felt sleepier post waking when on-call than when not on-call and felt sleepier in the low stress compared to the high stress condition (p <.001). Spatial performance was faster in both on-call conditions, compared to the control only (p<.001). Overall, results suggest that sleep inertia severity when on-call is not negatively impacted when anticipating a high-stress task.