Relação entre o uso noturno do telefone celular e o ciclo sono-vigília, resposta autonômica e processamento cognitivo matutino de universitários

Abstract

The college experience promotes changes in the lives of emerging adults, among which greater use of media, whose proximity to the beginning of sleep causes irregularity, poor sleep quality and sleep deprivation affecting basic cognitive processes that regulate performance, such as attention, working memory, inhibitory control, cognitive flexibility. However, performance and sleepiness can suffer a compensatory effect from brain areas that can be reflected in cortical activation autonomic activity. In this work, we assessed the impact of nighttime cell phone use on irregularities on sleep times and duration, sleep quality, social jetlag, daytime sleepiness, and cognitive performance. In parallel, the compensatory effect of the autonomic nervous system to sleep deprivation was assessed through heart rate variability (HRV). 59 students (44 women) from higher education courses in the field of biosciences completed the questionnaire "Sleep and Health" and the Epworth Sleepiness Scale. Then, they filled sleep diaries, where they recorded cell phone use after 6 pm and used actiwatches for 10 days. In this phase, they performed cognitive tests and underwent a collection of variables of autonomic response between 7 e 9 am. A GLM analysis was performed to evaluate the effect of cell phone use after 6 pm on the other variables. Also, 3 structural equation models were built to analyze the multiple prediction relationships between the variables studied. In school days, students slept and woke up earlier and reported higher levels of sleepiness upon waking. The greater use of cell phones predicted higher levels of daytime sleepiness (β = 0.016; p = 0.03) and HRV (β = 0.460; p = 0.001), as well as less cognitive flexibility (β = -0.064; p = 0.008), and a trend to less sustained attention (β = 0.115; p = 0.063). The indirect impact of cell phone use after 6 pm on cognition was assessed using structural equation analysis,considering its action via sleep quality (mean of night awakenings and wake after sleep onset) and sleep irregularity (social jetlag), as well as changesin HRV and EEG. However, no indirect effects of cell phone use on cognitive variables were found. Therefore, cell phone use after 6 pm was associated with an increase in daytime sleepiness with negative impacts on sustained attention and cognitive flexibility in the morning in university students. Also, cell phone use was associated with increased HRV, which may be due to the activation of the parasympathetic nervous system during cognitive effort.