Effect of morning exercise in sunlight on the sleep-wake cycle in adolescents.

Abstract

A delay in bedtime occurs in adolescence compared with childhood. However, the early waking that morning school hours impose leads to partial sleep deprivation. Although exposure to light is the most important regulator of circadian rhythm in mammals, physical exercise influences circadian synchronization. To assess the effect of morning physical exercise in sunlight on the sleep-wake cycle (SWC) in adolescents, 160 first-and second-year high-school students were exposed to classes in their usual classroom (Group C) or in a swimming pool exposed to sunlight (Group E) while physically exercising (EE; i.e., swimming) or resting (EL). At baseline, we applied Health and Sleep and Horne & Ostberg chronotype assessment questionnaires. One week later and during the intervention, we applied the Sleep Diary and Karolinska Sleepiness Scale. During the intervention we observed no changes in bedtime, time in bed and in indices of irregularity of bedtime and wake-up time. The changes observed in wake-up time (i.e., a delay in the EE group on Saturday), sleep quality (i.e., an improvement), and sleepiness (i.e., an increase) were also observed in the control group, discarding an intervention effect. We suggest that morning physical exercise in sunlight had no effect on SWC parameters, sleep quality, or daytime sleepiness, possibly because of the large irregularity in the SWC between weekdays and weekends in adolescent students as well as the low frequency and duration of exercise during the intervention. Therefore, studies that evaluate a higher frequency or duration of exercise are needed to assess its effect on the SWC in adolescents.

Health indicators associated with poor sleep quality among university students

“…In similar fashion, three studies carried out in Brazil with sedentary young adults did not identify any association between regular physical exercise and improvements in sleep patterns (12)(13)28) . Like these three cited Brazilian studies, the divergence between the data of this investigation and other investigations may arise from methodological divergences in the definition of physical activity or also from the low intensity of exercise carried out by young people.…”

Sleep, social behaviour and food consumption of schoolchildren of a large Brazilian city

“…The authors found that the increase in the prevalence of poor and very poor sleep quality increased the likelihood of schoolchildren always presenting sleep alterations and inadequate social behaviour in relation to those with good and very good sleep quality. Poor sleep quality seems to contribute to the development of sleep disorders, as well as depression, anxiety and low self-esteem (55) . Research conducted with Israeli children 7 to 13 years of age noted that lower sleep efficiency and higher nocturnal awakening predicted poor performance in processing emotional information (56) .…”

A Study on the Subjectivity of Parents Regarding “0th-Period Physical Education Class” of Middle Schools in Korea Using Q-Methodology

“…In this respect, morning exercise can draw academic significance in 2 of 11 studies targeting adolescents. For instance, consistent morning exercise participation, such as swimming in adolescents, positively affects the sleep-wake cycle [11]. In addition, Babadi et al [12] observed that adolescents who engaged in morning exercise at school had a lower prevalence of hypertension.…”