Work

Daily fluctuations in sleep duration and quality affect next-day processing speed performance in young and older adults: an intensive longitudinal everyday life study over 21 days

Year: 2025

Type: article

Abstract: STUDY OBJECTIVES: Knowledge about how day-to-day variations in sleep affect cognitive performance in real-world contexts is currently limited. This study investigated how daily fluctuations in sleep duration, efficiency, and quality affect next-day processing speed, and tested whether these associations differ between young and older adults. METHODS: A total of 158 young (18-30 years) and 168 older adults (55-75 years) participated in a 21-day intensive longitudinal design. Sleep duration and efficiency were measured using actigraphy, while sleep quality was assessed via sleep diaries. Processing speed was measured using a 60 s smartphone-based Digit Symbol Substitution Task, administered up to eight times per day. Multilevel mixed models tested the within- and between-person effects of sleep duration, sleep efficiency and sleep quality, as well as the effect of age group on processing speed. RESULTS: Within-person, a sleep duration shorter than their own average (p < .001), and a sleep quality poorer than their own average (p < .05) predicted poorer next-day performance. Between-person differences in sleep duration, sleep efficiency and sleep quality were not significantly associated with processing speed. Older adults showed worse performance than young adults (p < .001), but the effect of daily sleep fluctuations on performance did not significantly vary between age groups. CONCLUSIONS: Daily fluctuations in sleep duration and sleep quality are linked to processing speed in young and older adults in real-world contexts. Results suggest that within-person, day-to-day variations in sleep may be more important than between-person differences. Maintaining an adequate sleep duration each day may help prevent cognitive impairments in daily functioning across age groups.

Source: SLEEP

DOI: 10.1093/sleep/zsaf321

Authors: Johanna Schwarz, Malin Freidle, Wessel van Leeuwen, Jade Silfverling, Torbjörn Åkerstedt, Göran Kecklund

Institutions: Stockholm University, Karolinska Institutet

Language: English

Topic: Sleep and related disorders

Subfield: Experimental and Cognitive Psychology

Field: Psychology

Domain: Social Sciences

SDG: Good health and well-being

Open Access status: hybrid

Estimated APC paid: $4,388