Interaction of Age with Time of Day and Mental Load in Different Cognitive Tasks

Abstract

Extensive research has demonstrated that shiftwork produces deleterious effects on health because of the desynchrony it induces in the biological clock. The problem is even more crucial for older workers who present, in addition, various decrements in their cognitive functioning, particularly on attention and memory. The present study assessed whether age was related to task complexity as a function of time of day and time-on-task in a rapid rotating work-rest schedule. 24 subjects (12 juniors: 20-30 years and 12 seniors: 50-60 years) performed either a simple task (visual discrimination) or a complex task (descending subtraction) on three different moments of the day simulating the main shifts (morning, evening, and night). Analysis indicated that an age effect was only present on the more complex task, which was demanding in attentional resources and memory load. Seniors had no deficit in performance on the simple task compared to juniors. The effect of time of day was restricted to the simple task for both age groups. However, some differential strategies appear to distinguish juniors and seniors, specifically on accuracy during the night, suggesting that subjects of different ages cope with cognitive tasks in different ways and that perhaps some adverse effects apparently associated with aging could be counteracted by efficient strategies, but not others.

Diurnal variation of cognitive performance and perceived difficulty in dart-throwing performance in 9–10-year-old boys

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Sleep and Health Consequences of Shift Work in Women

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Let them sleep: The effects of a scheduled nap during the night shift on sleepiness and cognition in hospital nurses

“…Furthermore, the authors previously reported several factors associated with sleepiness and performance during the night shift (Zion, Drach‐Zahavy, & Shochat, ; Zion & Shochat, ). Older shift workers were more vulnerable to the negative impacts of night work on cognitive performance (Bonnefond et al, ; Bonnefond, Rohmer, Hoeft, Muzet, & Tassi, ; Tadinac, Sekulić, Hromatko, Mazul‐Sunko, & Ivancić, ), whereas younger workers reported increased sleepiness (Bonnefond et al, ; Härmä, Sallinen, Ranta, Mutanen, & Müller, ; Zion et al, ). In addition, morning chronotypes preferred going to bed early and experienced high levels of sleepiness during night shifts (Gamble et al, ; Saksvik, Bjorvatn, Hetland, Sandal, & Pallesen, ; Seo, Matsumoto, Park, Shinkoda, & Noh, ; van de Ven et al, 2).…”