Altered subjective time perception and cognitive performance following three days of sleep restriction in healthy adults

The intricate role of sleep in sustaining critical physiological functions and preserving cognitive integrity is well-established. Inadequate sleep, whether in duration or quality, profoundly impairs fundamental cognitive functions, including memory consolidation, sustained attention, executive decision-making, and temporal perception. This study endeavors to explore the effects of short-term sleep restriction on subjective time perception employing both retrospective and prospective paradigms to unveil how acute sleep restriction reshapes temporal cognition in healthy adults. Following ethical approval, 31 healthy volunteers aged between 18 and 35 years participated. The experimental protocol which included assessments conducted under two conditions: after four consecutive nights of regular sleep and following three nights of sleep restriction, during which participants' sleep duration was reduced by two hours per night. Subjective time perception was evaluated using both retrospective and prospective time generation tasks (RTP and PTP). To assess cognitive performance, participants completed the Stroop test, which measures selective attention and cognitive flexibility, and the Wechsler Memory Scale-III (WMS-III), a validated instrument for evaluating short-term and working memory functions. The RTP after sleep restriction showed a significant prolongation compared to regular sleep duration (20.2 ± 8.8 vs 26.6 ± 12.3 sec, respectively; ANOVA <i>p</i> < 0.001). Short-term and working memory performances decreased after sleep restriction (10.8 ± 1.9 vs 10.0 ± 2.1 sec and 12.3 ± 2.1 vs 11.4 ± 2.3 sec respectively; ANOVA <i>p</i> ≤ 0.001 for both). Even moderate sleep restriction (e.g. a two-hour reduction) disrupts temporal cognition and memory, underscoring the critical need for sufficient sleep to sustain optimal cognitive performance in high-demand scenarios.