Effects of Sleep Reduction During the Week in Sustained Attention

*Corresponding autor e-mail: jcortezg@gmail.com Introduction: The majority of the people living in cities works 5 days a week (Monday to Friday) and rest during weekends (Saturday and Sunday). People working in this schedule tend to sleep less during weekdays, compared to weekends. Sleep reduction during weekdays may affect cognitive performance. Attention is a basic cognitive process, with 4 components: tonic alertness, phasic alertness, selective attention and sustained attention. Sustained attention is the capacity to respond efficiently to the environment during prolonged periods. There are three indices of sustained attention: general stability of efficiency, time on task stability and short-term stability. The objective of this study was to analyze the effects of sleep deprivation during the week in sustained attention. Methods: Participants were 19 undergraduate students attending school at a morning shift (07:00-13:00 h). 11 students were registered during weekdays (weekday group), whereas 8 students were recorded during weekends (weekend group). All participants kept a sleep-wake diary during 11 days. Then, each participant was recorded in the laboratory from 20:00 h to 02:00 h. Sleepiness, tiredness and responses on a Continuous Performance Task (CPT) were recorded at 2 h intervals. This task required the participant to press 1 to any number (except “9”) appearing at the center of the computer screen, to press 2 when a “9” appeared, and to press 3 when a “4” appeared after the “9”. The CPT had 27 blocks with 20 stimuli each. Three indices of sustained attention were assessed: general stability (standard deviation of correct responses and reaction time), time on task stability (linear regression of correct responses and reaction time) and short-term stability (hit runs and error runs). Results: Compared to the weekend group, the weekday group slept less the night preceding the recording session (weekday group 6:16±0:34 h, weekend group 9:28±1:24 h, U=0, p <0.0001). The reduction in sleep was due to differences in waking time (waking time: weekday group 05:25±0:24 h, weekend group 09:11±1:05 h, U=0, p <0.0001; bedtime: weekday group 23:08±0:41 h, weekend group 23:42±1:05 h, U=32.50, NS). Both groups showed changes in all indices of sustained attention with time of day. Compared to the weekend group, the weekday group showed less stability and an increase in isolated hits at 02:00 h (SD of reaction time F=3.64, p <0.01; isolated hits F=4.85, p <0.05). Conclusion: In conclusion, sleep reduction during the week impair sustained attention at night. This can decrease efficiency in many activities, such as driving a car or working at night. Publication History Article published online: 16 June 2026 © 2009. Brazilian Sleep Academy. This is an open access article published by Thieme under the terms of the Creative Commons Attribution-NonDerivative-NonCommercial License, permitting copying and reproduction so long as the original work is given appropriate credit. Contents may not be used for commercial purposes, or adapted, remixed, transformed or built upon. (https://creativecommons.org/licenses/by-nc-nd/4.0/) Thieme Revinter Publicações Ltda. Rua Rego Freitas, 175, loja 1, República, São Paulo, SP, CEP 01220-010, Brazil