A chain mediating model of the impact of physical exercise on sleep quality | BMC Public Health

In the fast-paced modern society, sleep quality has become a critical indicator of individual health and quality of life. Among various populations, college students represent a particularly vulnerable group, as their sleep quality directly impacts academic performance, mental health, and long-term career development. Alarmingly, over 40% of college students exhibit clinically significant sleep disturbances-a prevalence substantially higher than that observed in the general population [1]. While insufficient physical activity among adolescents remains a global public health concern [2]; physical activity has been proven to help improve sleep [3], and participation in exercise becomes one of the important factors affecting sleep quality [4]. Physical exercise, a subset of physical activity, is structured, planned, and repetitive, with the objective of improving or maintaining physical fitness (e.g., running, strength training, aerobic exercises). Therefore, the relationship between college students’ physical exercise and sleep quality is worth studying.

According to the 53rd Statistical Report on the Development of the Internet in China released by the China Internet Network Information Center (CNNIC) in Beijing, by December 2023, the scale of netizens in China reached 1.092 billion, with an Internet penetration rate of 77.5%, and the average daily Internet usage time per person was 3.7 h. Some scholars define prolonged use of mobile phones as using mobile phones for more than four hours per day, which can lead to mobile phone dependence, also known as mobile phone addiction or irrational mobile phone use [5], is described as a state of obsession caused by specific motives, long-term use of mobile phones, and damage to individual psychological and social functions. College students, as the main users of smartphones, exhibit particularly noticeable dependence. Previous studies have shown that negative behaviors (such as mobile phone dependence) are closely related to sleep quality [6]. College students’ mobile phone usage behavior has a significant impact on sleep quality; the higher the frequency and longer the duration of mobile phone use before sleep, the worse the sleep quality [7]. In addition to mobile phone dependence, a significant factor affecting college students’ sleep quality is the widespread problem of insufficient sleep [8], which may be related to factors such as mobile phone dependence. A systematic review of 23 randomized controlled trials indicates that exercise intervention may help reduce smartphone addiction [9]. These findings collectively position mobile phone dependence and sleep duration as critical mediators in the relationship between physical exercise and sleep quality.

The impact of physical exercise on sleep quality

The biopsychosocial model provides a comprehensive framework for understanding sleep health through the dynamic interaction of physiological, psychological, and social determinants [10]. Specifically, physical exercise improves sleep quality through the synergistic effects of different pathways: physiological adaptations; psychological mechanisms such as strengthened self-regulation capacities that redirect attention from maladaptive behaviors (e.g., smartphone overuse) to health-promoting activities; and social reinforcement through group-based exercise environments that foster behavioral consistency [11]. This tripartite mechanism challenges reductionist biomedical paradigms by demonstrating that sleep outcomes fundamentally depend on integrated biological-behavioral-social processes.

A substantial body of research indicates that exercise can improve sleep quality across various populations. Exercise primarily modulates negative emotions such as tension and anxiety, inhibits excessive arousal states, and both aerobic training and combined aerobic and resistance training can enhance sleep quality in patients with primary insomnia [12]. Aerobic combined with resistance exercise intervention can improve sleep quality in gastric cancer chemotherapy patients [13]. Aerobic exercise training significantly improves lung function and sleep quality in patients with stable chronic obstructive pulmonary disease [14]. Home-based aerobic exercise can improve sleep disturbances and quality of life in liver cancer patients [15]. Sedentary behavior is a risk factor for sleep disorders; an investigation and analysis of sedentary and exercise behaviors in 23,000 subjects show that exercise is effective in improving sleep disorder symptoms in sedentary groups [16]. Studies have shown that chronic fatigue syndrome patients significantly improved sleep disturbances after three months of fitness Qigong practice [17]. Comprehensive non-pharmacological interventions, including physical exercise and dietary management, for sleep disorder patients have a positive impact on sleep quality, general physical symptoms, and some physical examination indicators of sleep disorders [18]. Exercise intervention in cancer patients after treatment for three months resulted in longer sleep duration, which has significant clinical implications [19]. Exercise intervention in urban elderly insomnia patients led to the subjects sleeping “better” with higher sleep quality [20]. Multiple meta-analyses have shown the effectiveness of exercise intervention on sleep quality. Twenty-two randomized controlled trials included in the analysis showed that self-reported sleep quality, insomnia severity, and daytime sleepiness can be improved or improved through exercise treatment [21]. In 23 high-quality trials, including data from 1,269 patients who received exercise intervention and 1,203 patients who received medication treatment or no intervention (control), meta-analysis showed that exercise intervention has a significant effect on treating primary insomnia, and exercise intervention has a significant positive impact on primary insomnia, especially for elderly patients [22]. A total of 12 randomized controlled trials involving 1,493 subjects were included; exercise intervention programs included yoga, walking, fitness Qigong, and aerobic exercise, and meta-analysis showed that exercise effectively improves sleep in peri-menopausal women, having a significant impact on sleep quality and insomnia symptoms in peri-menopausal women [23]. Based on these extensive studies on the impact of physical exercise on sleep quality, Hypothesis H1 is proposed: Physical exercise has a positive impact on enhancing sleep quality.

The impact of physical exercise on mobile phone dependence

Self-regulation theory provides a robust theoretical foundation for understanding how physical exercise mitigates mobile phone dependence. According to Zimmerman’s cyclical model of self-regulated learning (SRL), structured exercise regimens—characterized by goal-setting, self-monitoring, and reflective adaptation—strengthen executive functioning and impulse control [24]. The enhancement of self-regulation capacity triggered by exercise effectively reduces the impulse associated with the reward mechanism of smartphones; each increment in physical exercise directly displaces screen time, thereby weakening the triggers of dependence. This process not only regulates individual behavioral motivations from a psychological perspective but also reduces contact with mobile phones at the behavioral level, thus exerting a dual inhibitory effect on mobile phone dependence.

Engaging in physical exercise provides an opportunity to reduce exposure to smartphones, potentially decreasing mobile phone dependence. The issue of mobile phone dependence due to prolonged use should not be overlooked, as it can severely impact one’s physical and mental health [25]. Studies have found that the rate of mobile phone addiction (MPAI) among college students in China is 23% [26]. Prolonged and frequent use of the internet and smartphones often results in a sedentary lifestyle, and research indicates a significant negative correlation between physical exercise and mobile phone dependence [27, 28]. Increasing the frequency of college students’ participation in physical activities each week is equivalent to reducing their habitual long periods of sedentary behavior in daily life, replacing it with a healthier lifestyle that less frequently involves the use of mobile phones [29]. A survey of 650 Chinese college students showed that higher levels of physical activity in terms of aerobic endurance are associated with lower degrees of mobile phone dependence [30]. A 12-week experiment demonstrated that group basketball and Baduanjin exercises reduced smartphone dependence, and this effect continued to be valid for two months [31]. Open and group-based sports had similar effects on improving college students’ mobile phone dependence, while closed sports showed a more sustained effect [32]. Physical exercise can serve as an intervention for mobile phone dependence among college students [33]. Neurobiological evidence suggests that exercise can reduce internet addiction by improving the morphology of specific parts of the central nervous system; protecting the autonomic nervous system; and controlling reward impulses, meaning that exercise seems to alleviate internet addiction by regulating the central and autonomic nervous systems [34]. Based on this, Hypothesis H2 is proposed: Physical exercise has a positive impact on reducing mobile phone dependence.

The impact of mobile phone dependence on sleep quality

Self-regulation theory posits that an individual’s behavior is influenced by internal motivations and external environmental factors [35]. Prolonged smartphone use before bedtime induces cognitive overload through information saturation and emotional arousal, delaying sleep onset and thereby disrupting normal sleep patterns.

Studies have indicated that the use of electronic devices such as televisions or computers that emit bright light before bedtime can adversely affect an individual’s sleep quality; with the widespread use of smartphones, this negative impact may be further exacerbated. In a questionnaire survey of 1,312 college students in Guangzhou, researchers found that students who used their phones for more than one hour before sleep and those with a higher degree of mobile phone dependence had the highest prevalence of sleep quality disorders [36]. A survey of 987 medical college students showed that the higher the degree of mobile phone dependence, the poorer the sleep quality, the shorter the sleep duration, the lower the sleep efficiency, and the more likely they were to experience sleep disorders [37]. Mobile phone dependence can significantly predict sleep [38]; mobile phone dependence directly affects sleep quality, and the greater the degree of mobile phone dependence among college students, the poorer the sleep quality [39]. Based on this, Hypothesis H3 is proposed: Mobile phone dependence will reduce sleep quality.

The impact of mobile phone dependence on sleep duration

The Resource Allocation Theory explains how individuals balance their limited time and energy among various activities [40]. This theory is particularly applicable to exploring how individuals make choices and trade-offs between daily activities, such as physical exercise and smartphone usage. In modern society, smartphones have become an indispensable part of people’s daily lives, but excessive use, especially at night, is widely believed to have a negative impact on sleep quality. Studies have indicated that as smartphone usage time increases, individuals tend to have shorter sleep durations and later bedtimes, changes that can lead to a decline in sleep quality [41]. Mobile phone addiction has a negative effect on the sleep quality and various dimensions of college students [42]. Surveys conducted among college students show that sleep deficiency is a common problem among adolescents, and smartphone dependence is an important predictive factor for sleep insufficiency [43]. A meta-analysis of 14 studies found a significant positive correlation between adolescent smartphone dependence and sleep quality [44]. These studies emphasize the importance of a healthy lifestyle in preventing smartphone dependence and maintaining good sleep habits. Therefore, Hypothesis H4 is proposed: Mobile phone dependence has a negative impact on sleep duration. According to the Pittsburgh Sleep Quality Index (PSQI), longer sleep duration is associated with higher sleep quality; extending sleep time can improve sleep quality. Hypothesis H5 is proposed: Sleep duration can enhance sleep quality. Studies have pointed out that comprehensive intervention measures, primarily exercise, can effectively alleviate symptoms of smartphone dependence among college students and significantly improve their sleep quality [45]. With appropriate intervention measures, sleep patterns damaged by smartphone dependence can be improved [46].

In summary, physical exercise, as a positive lifestyle choice, has been proven to have potential positive effects on improving sleep quality. However, existing studies have predominantly focused on the direct relationship between physical exercise and sleep quality, with limited exploration of the underlying psychological and behavioral pathways, particularly the role of smartphone dependence. Based on this, we select four variables: physical exercise, mobile phone dependence, sleep duration, and sleep quality. By constructing a mediation effect model, we reveal the complex relationship between physical exercise and sleep quality, attempts to identify a chain mediating mechanism, provides empirical support for the design of comprehensive interventions targeting behavioral addiction and sleep physiology among college students. Based on the above hypotheses, a relationship model between physical exercise, mobile phone dependence, sleep duration, and sleep quality is constructed, as seen in Fig. 1. It is hypothesized that there is a direct effect between physical exercise and sleep quality, an indirect effect of mobile phone dependence between physical exercise and sleep quality, and a chain mediating effect of mobile phone dependence and sleep duration between physical exercise and sleep quality.

Theoretical model of mobile phone dependence and sleep duration in the relationship between physical exercise and sleep quality