Abstract
IntroductionThe contribution of circadian system and sleep pressure influences on executive performance as a function of age has never been studied. The aim of our study was to determine the age-related evolution of inhibitory motor control (i.e., ability to suppress a prepotent motor response) and sustained attention under controlled high or low sleep pressure conditions.Methods14 healthy young males (mean age = 23±2.7; 20–29 years) and 11 healthy older males (mean age = 68±1.4; 66–70 years) were recruited. The volunteers were placed for 40 hours in “constant routine”. In the “Sleep Deprivation SD” condition, the volunteer was kept awake for 40 hours to obtain a high sleep pressure condition interacting with the circadian process. In the “NAP” condition, the volunteer adopted a short wake/sleep cycle (150/75 min) resulting in a low sleep pressure condition to counteract the homeostatic pressure and investigate the circadian process. Performances were evaluated by a simple reaction time task and a Go/Nogo task repeated every 3H45.ResultsIn the SD condition, inhibitory motor control (i.e., ability to inhibit an inappropriate response) was impaired by extended wakefulness equally in both age groups (P<.01). Sustained attention (i.e. ability to respond accurately to appropriate stimuli) on the executive task decreased under sleep deprivation in both groups, and even more in young participants (P<.05). In the NAP condition, age did not influence the time course of inhibitory motor control or sustained attention. In the SD and NAP conditions, older participants had a less fluctuating reaction time performance across time of day than young participants (P<.001).ConclusionAging could be a protective factor against the effects of extended wakefulness especially on sustained attention failures due to an attenuation of sleep pressure with duration of time awake.
Highlights
The contribution of circadian system and sleep pressure influences on executive performance as a function of age has never been studied
The circadian system driven by the endogenous biological clock and the sleep-wake homeostatic process which is dependent on the duration of prior wakefulness, interact to regulate sleep and wakefulness according to nycthemeral variations
The main factor ‘‘time’’ was significant (F10,230 = 16.0, P,.001) with significantly slower reaction times during (P,.001) and after (P,.001) the biological night compared to the baseline day
Summary
The contribution of circadian system and sleep pressure influences on executive performance as a function of age has never been studied. Marked changes appear in sleep timing, quality and duration, such as decreases in sleep depth (measured by arousal threshold), sleep intensity (measured by slow wave activity (SWA)), sleep continuity (measured by awakenings during the night), and sleep duration [3]. This reduction in sleep need may reflect age-related changes in the homeostatic and/or circadian aspects of sleep regulation [4,5]. Older people display a shallower dissipation of sleep pressure, as indexed by reduced SWS and slow wave activity (SWA) dynamics across the night [10,11]
Talk to us
Join us for a 30 min session where you can share your feedback and ask us any queries you have