New study examines the connection between daily activity and sleep quality in young adults

A study in China that tracked students’ physical activity for seven days found that those with insomnia slept better on days when they engaged in more vigorous physical activity or were more sedentary than usual. Conversely, their sleep worsened on days when they engaged in more light physical activity than usual. However, no significant association was found between physical activity and sleep quality in students without insomnia. The research was published in Psychology of Sport & Exercise.

Sleep problems include difficulties in falling asleep, staying asleep, or achieving restful sleep, all of which can negatively impact daily functioning. Insomnia is one of the most common sleep disorders, characterized by trouble falling or staying asleep. Another serious condition, sleep apnea, causes repeated interruptions in breathing during sleep, leading to poor rest and health risks. Restless legs syndrome, meanwhile, triggers uncomfortable sensations in the legs, making it difficult to relax at night.

Sleep disturbances are a common complaint among young adults. Estimates suggest that around 33% of higher education students experienced sleep problems during the 2020–2021 COVID-19 pandemic. A study of Chinese university students found that 40% slept fewer than seven hours per day. Factors such as stress, anxiety, irregular sleep schedules, and excessive screen time contribute to these issues.

Study author Kaixin Liang and colleagues sought to investigate the daily relationship between physical activity levels and sleep quality among young adults. They categorized physical activity into three types: moderate to vigorous physical activity, light physical activity, and sedentary behavior.

The study included 147 university students recruited from Shenzhen, China. Participants were required to be between 18 and 29 years old, maintain normal sleep patterns and physical functioning, and not be involved in any programs that might affect sleep quality, such as psychotherapy. The average participant age was 22 years, and 67 were male.

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The study lasted seven days and eight nights, during which participants wore an activity-tracking device in the form of a wristband (Fitbit Inspire HR). They were instructed not to use any reminders related to physical activity (e.g., apps prompting them to stand or move) and to avoid disruptions to their normal lifestyles.

Each day at around 9 a.m., participants received a questionnaire asking them to assess their sleep quality from the previous night, which they were required to complete by noon. Students received 80 RMB (approximately $11) for their participation. They also completed an assessment of insomnia symptoms over the past month using the Youth Self-Rating Insomnia Scale.

The results showed that 41 participants had insomnia symptoms, while 106 did not. Among those without insomnia symptoms, there was no association between physical activity levels and sleep quality. However, for students with insomnia symptoms, sleep efficiency improved on days when they engaged in either more vigorous physical activity or more sedentary behavior than usual. In contrast, their sleep efficiency worsened on days when they increased light physical activity at the expense of vigorous activity and sedentary behavior.

“For young adults with insomnia symptoms, replacing LPA [light physical activity] with MVPA [moderate to vigorous physical activity] on a given day may improve their sleep efficiency that night,” the study authors concluded.

The study contributes to the scientific understanding of the links between physical activity levels and sleep quality. However, it is important to note that the research did not account for the nature of the activities observed. It is possible that the associations found in students with insomnia were not due to physical activity itself, but rather to the meaning and nature of those activities.

The paper, “Move more today, sleep better tonight? Daily associations between physical activity and sedentary behavior with sleep among young adults with and without insomnia symptoms,” was authored by Kaixin Liang, Flora Le, Peilian Chi, Sitong Chen, Liuyue Huang, and Xinli Chi.