Sleep and physical activity are fundamental lifestyle factors that significantly influence overall health and wellbeing (1). Understanding the interplay between sleep and physical activity habits is crucial for developing effective strategies to enhance health outcomes. Numerous studies have explored the complex relationship between these behaviors, highlighting their bidirectional nature and the intricate mechanisms underlying their interactions. Research has shown that physical activity can have a substantial impact on sleep quality and duration. Regular physical activity has been associated with improved sleep outcomes, including enhanced sleep efficiency (SE), reduced sleep latency, and increased total sleep time (2, 3). In addition, higher levels of physical activity have been linked to a decreased risk of developing sleep disorders such as insomnia (4). However, the timing, intensity, and duration of physical activity can influence sleep, with vigorous exercise close to bedtime potentially disrupting sleep (5).

Conversely, sleep plays a crucial role in physical activity performance and recovery. Adequate sleep duration and quality have been associated with better athletic performance, cognitive function, and motor skills (6, 7). Insufficient sleep, on the other hand, can lead to decreased exercise capacity, impaired reaction time, and increased injury risk (8, 9). Moreover, sleep has been shown to affect the physiological processes involved in postexercise recovery, including muscle repair and glycogen restoration (10). Furthermore, the relationship between sleep and physical activity extends to the regulation of energy balance and weight management. Sleep deprivation (SD) has been associated with alterations in appetite-regulating hormones, such as increased ghrelin levels and decreased leptin levels, leading to increased food intake and a higher risk of obesity (11). Physical activity can modulate these hormonal profiles, potentially mitigating the negative effects of sleep deprivation on energy balance and weight control (12).

Importantly, sleep disorders can significantly impact physical activity engagement and performance. Conditions such as obstructive sleep apnea have been associated with reduced physical activity levels and exercise capacity (13). Conversely, physical activity interventions, including exercise training and physical therapy, have shown promise in improving sleep quality and reducing the risk of sleep disorders (14, 15). The complex relationship between sleep and physical activity involves multiple underlying mechanisms. Circadian rhythms, hormonal regulation, and neural pathways play key roles in coordinating the interactions between these behaviors (16, 17). Moreover, nutrition has emerged as a significant factor that can influence both sleep and physical activity outcomes (18). Optimal dietary patterns and nutrient intake can support healthy sleep and physical activity, while inadequate nutrition can impair performance in both domains.

To comprehensively understand the interplay between sleep and physical activity habits, this review synthesizes existing knowledge across a variety of research domains. We will explore the impact of physical activity on sleep quality and duration, the effects of sleep on physical activity performance and recovery, and the role of sleep in energy balance and weight management. In addition, we will investigate the influence of sleep disorders on physical activity engagement and the potential benefits of physical activity interventions for improving sleep outcomes. Moreover, we will examine the impact of timing, intensity, and duration of physical activity on sleep, and the reciprocal effects of sleep duration and quality on physical activity. Furthermore, we will delve into the potential underlying mechanisms, including circadian rhythms, hormonal regulation, and neural pathways. The interrelationships between nutrition, sleep, and physical activity will also be explored, along with potential synergies for intervention strategies. Lastly, we will highlight future perspectives, such as advancements in wearable technology, personalized interventions, and precision medicine approaches, to further enhance our understanding and optimize the interplay between sleep and physical activity habits.

Narrative reviews are essential for academic knowledge as they provide a comprehensive understanding of a topic, integrate diverse evidence sources, stimulate critical analysis, identify research gaps, and guide future investigations. Unlike systematic reviews, narrative reviews capture the breadth and depth of a subject, serving as valuable educational tools and facilitating knowledge acquisition. They excel at synthesizing qualitative and quantitative research, fostering discussions, generating hypotheses, and proposing theoretical models. Moreover, narrative reviews adapt to evolving research, ensuring relevance and contributing to the advancement of knowledge across various academic disciplines.

To achieve the objectives of this narrative review, a comprehensive assessment was conducted, incorporating primary sources, such as scientific publications, and secondary sources, such as bibliographic indexes, web pages, and databases. The primary focus of this narrative review was to gain a thorough understanding of the intricate relationship between sleep and physical activity habits. The search criteria encompassed English manuscripts published between 2000 and 2025, except for classic literature, while excluding gray literature. Furthermore, additional references were sought through retrieved articles, practice guidelines, editorials, and letters. To encompass the multifaceted nature of mental health, a range of databases including MedLine, Cochrane, Embase, PsychINFO, and Cinahl were utilized. Studies addressing topics related to nutrition, physical activity, sleep, sleep quality, sleep disorders, physical performance, recovery, activity habits, medicine, and wearable technology were included. Exclusion criteria consisted of research falling outside the specified time, topics beyond the scope of this review, and unpublished studies, books, conference proceedings, abstracts, and dissertations. We extracted the information and allocated the data based on our respective areas of expertise.

Sleep is a fundamental component of physical and mental health, with current recommendations suggesting a minimum of 7 h of sleep per night for adults to support optimal functioning. In recent years, growing evidence has highlighted physical activity as a key behavioral factor capable of modulating sleep quality and, to a lesser extent, sleep duration, reinforcing the bidirectional relationship between these two lifestyle behaviors (19).

Numerous studies have shown that adequate sleep duration and quality are closely linked to improved physical activity development. Hence, adequate rest allows the body to recover and repair itself, leading to enhanced physical performance and skill acquisition. During sleep, the brain consolidates memories and motor skills acquired during physical activity. In turn, sufficient sleep facilitates the encoding and integration of new movement patterns, enhancing motor learning and coordination (37, 38). Moreover, sleep plays a critical role in hormonal regulation, including the secretion of growth hormone (GH), which is essential for muscle growth and tissue repair. Adequate sleep promotes optimal hormone balance, facilitating the development of lean muscle mass and overall physical performance (39).

Several authors have highlighted the detrimental impact of sleep loss on exercise performance. Sleep loss has been shown to exert a harmful effect on individuals, with numerous adverse consequences documented due to sleep deprivation. Thus, sleep deprivation involves a reduction in muscular strength and endurance (40, 41), a modification in emotional mood, including decreased motivation levels and increased perceived effort (42–44), and alterations in cognitive processing developments, such as diminished fine motor skills (45). Other authors have described the negative impact of sleep deprivation on strength. In a study conducted of judokas, partial sleep deprivation timed at the end of the night decreased muscle strength and power during short-term maximal performances (46). It has also been described that sleep deprivation may have an adverse impact on endurance. Recent research has shown that total sleep deprivation in cyclists can impair prolonged self-paced endurance performance by approximately 10% for a duration of around 60 min (47). This highlights the significant impact sleep deprivation can have on an individual's ability to sustain endurance activities at a high level. Similarly, in a study conducted in military populations, it was observed that partial sleep deprivation can increase both cardiorespiratory and psychological strain, ultimately limiting an individual's capacity for high-intensity endurance activities (48). Sleep disruption has also been negatively related to a reduction in aerobic power. In one study, athletes completed cycling tests under different sleep conditions, including normal sleep, partially deprivation (4 h), and complete sleep deprivation. Aerobic performance was impaired by 11.4% under complete deprivation and 4.1% under partially deprivation (49). Sleep deprivation negative impacts tasks requiring a high level of precision. For example, in a study of dart-throwing athletes, sleep deprivation was associated with diminished alertness, increased fatigue, and small but measurable declines in performance (45).

On the topic of physical recovery, several researchers have pointed out how sleep loss could have a negative impact. Optimal recovery is essential for repairing damaged tissues, replenishing energy stores, and adapting to the physiological demands of exercise. Sleep deprivation disrupts these recovery processes, compromising the body's ability to repair and restore itself after physical activity. These findings may be explained by the fact that sleep disruption may compromise GH release, which has been extensively related to sleep regulation (50). During sleep, the body releases GH, which plays a crucial role in tissue repair and muscle growth. However, inadequate sleep can disrupt the normal secretion of GH, impairing the body's ability to recover effectively. Recent literature has emphasized the key role that GH plays in regulating protein anabolism (51). This mechanism is mediated through IGF1-dependent endocrine and paracrine processes, as well as IGF1-independent pathways. The overall impact of GH on whole-body protein metabolism involves the redirection of amino acids toward synthesis, while reducing their irreversible oxidative loss. However, it is important to note that the effects of GH on different tissues vary, with distinct impacts on muscle tissue compared to extra-muscular tissues. In addition to its effects at the protein level, GH also involves metabolic processes, which promote energy production in muscle cells through different biochemical sources. Hence, GH has been described as enhancing glycogenolysis and gluconeogenesis as well as stimulating lipid oxidation and diminishing carbohydrate utilization (52, 53). Moreover, apart from GH activity, sleep deprivation can also impact glycogen replenishment, which is vital for restoring energy stores in the muscles and liver. Hence, glycogen serves as a readily available source of glucose when the body requires energy. In one study, 10 athletes underwent 30 h of sleep deprivation during consecutive-day intermittent sprint performances, after which their muscle glycogen content was examined. The study involved a single-day “baseline” session, followed by two consecutive-day experimental trials. These trials were separated by either a normal night's sleep or a period of no sleep. As a result, individuals who were sleep deprived had significantly reduced muscle glycogen rates compared to those who had sufficient sleep (54). This decrease in glycogen replenishment can result in decreased energy availability during subsequent exercise sessions, hindering overall performance and recovery. These results highlight the importance of adequate quality and duration for restoring body functioning and supporting recovery after exercise. Moreover, incorporating daytime napping has been suggested as a beneficial approach to enhance recovery, particularly in intensive training regimens that involve multiple training sessions within a single day (55).

The biological mechanisms that regulate sleep are determined by the genetic information encoded by the sensory marker light. Within this framework, essential physiological processes that facilitate the production of sleep can be differentiated and are activated at different intensities throughout the 24-hour light-dark cycle (56, 57). The purpose of these processes is to maintain the internal balance of the sleep–wake periods (58).

Different hormones and cellular assemblies involved in sleep-related processes have been identified. Melatonin, which is produced in the pituitary gland and synthesized from tryptophan, is released into the bloodstream, and reaches its highest levels during the night (59). This hormone acts mainly on the suprachiasmatic nucleus (SCN), which maintains neuronal circuits connected to the retina, responsible for detecting sunlight (60).

Conversely, adenosine facilitates reactive homeostasis via cellular metabolic processes linked to neural activity (61). Adenosine is an endogenous purine nucleoside and has a negative dromotropic effect (62). It accumulates in the lateral hypothalamus and can inhibit information access by binding to receptors in the ventrolateral preoptic region, allowing the arrest of ascending reticular system activity (63).

In addition, another factor regulating sleep is body temperature. At the end of the day, daily activity decreases, accompanied by a reduction in body temperature. This allows one to enter a state of rest, characterized by a decrease in neural activity and the induction of sleep. Body temperature usually decreases at the onset of sleep and during the second stage of the full cycle, when it reaches its lowest levels (64, 65).

During sleep, there is secretion of different hormones such as the thyroid-stimulating hormone secreted in the pituitary gland, the GH secreted in the hypothalamus, and cortisol secreted in the adrenal glands (66). These hormones contribute to maintaining physiological homeostasis in living beings and are essential for hormonal stabilization (67, 68).

Endocrine homeostasis is closely related to different neurological processes of brain repair and restoration of executive functions (69). For example, during deep sleep, the consolidation of learning and memory is established, particularly during rapid-eye movement (REM) phases (70). Sleep also plays a fundamental role in the induction and regulation of humoral and cellular immunity (71). Cellular immunity is activated through tumor necrosis factor (TNF) and interferon, which drive cells determined for phagocytosis of harmful particles or viruses. Specialized cells, such as natural killer and monocytes, produce IL4, IL6, IL10, and IL13 during sleep. Sleep cycle disturbances can impair immune modulation and the ability to deal with harmful or dangerous cells (72).

Energy balance is maintained through several processes, which can be genetic and environmental, including stress, diet, physical activity, microbiota, and sleep (73, 74). However, all of them are activated through the genes MC4R and FTO. MC4R, a G protein-coupled receptor, regulates appetite through the hypothalamic leptin–melanocortin pathway. FTO encodes the enzyme FTO, a member of the Fe (II) family and 2-oxoglutarate-dependent oxygenase. This is involved in different functions, such as the demethylation of nucleic acids in vitro (75–77).

Sleep determines the release of hormones that have intracellular reparative capacity, as well as those hormones that are involved in the regulation of energy balance and weight control (78, 79). When sleep disturbances occur, the efficiency of the neuroendocrine system is compromised, as in the case of sleep apnea. This pathology is dangerous because normal air exchange is interrupted, leading to high cardiac excitation, high levels of stress, and shortness of breath (80, 81).

For all these reasons, there is growing interest in the relationship between sleep and eating patterns, energy balance, and body weight. Recent studies have demonstrated a direct relationship between adequate sleep patterns and metabolic alterations, which otherwise contribute to pathologies such as obesity, metabolic syndrome, or intestinal alterations (82). Studies have shown that the higher the quality of sleep, the greater the chances of reducing body mass index. Similarly, the lower the quantity and quality of sleep during the first few years of life, the higher the risk of obesity in childhood and adulthood (83, 84). Other studies using physiological sleep measures such as actigraphy or polysomnography (PSG), which provide records motor activity, have reported data on sleep deprivation and its direct association with increased risk of overweight and obesity (85, 86).

In animal models, previous studies have shown that sleep modulation is altered during the development of obesity, suggesting that the regulatory mechanisms of sleep and body weight may be interconnected (87). Sleep deprivation has been linked to alterations in hypothalamic peptide signaling, particularly within the orexin neuropeptide system, in the lateral and posterior hypothalamus (88). In addition, after a few days of sleep deprivation, the plasma concentration of leptin is reduced while increasing ghrelin levels, a hormone involved in the regulation of appetite and nutritional balance. Ghrelin is also involved in other physiological processes such as insulin secretion (89, 90). In studies in which people were maintained on a 4-h daily sleep schedule, a significant decrease in glucose tolerance was observed, as well as increases in plasma insulin concentration and insulin-like growth factor or IGF-1, a hormone that modulates growth hormone effects (91). Moreover, sleep deprivation affects the proper functioning of glucose homeostasis, and altered sleep patterns are implicated in insulin sensitivity and glucose tolerance. Selective sleep deprivation in the third stage, or low non–rapid eye movement sleep (SNREM), decreases insulin sensitivity and physiological modifications, producing a prediabetic state (92). This indicates that sleep is closely tied to the regulation of glucose metabolism. Alterations in sleep patterns increase the risk of developing pathologies related to body weight (77, 93).

Sleep is widely acknowledged to play an essential role in maintaining healthy mental and physical functioning (94, 95). Despite this significance, there is still a lack of understanding regarding the rationale for why people sleep. Sleep's fundamental function in metabolic balance has been established, and recent investigations have shown that sleep regulates key molecular pathways (96). Light, jet lag (97), and diet (98) are just a few of the environmental elements that can affect how long and how well you sleep, but genetics also plays a role (99). Despite the complexity surrounding the necessity, rationale, and results of sleep, sleep is an essential function for humans. Human adaptability to physiological and psychological stressors has a significant impact on physical activity outcomes and is influenced by a wide range of factors, such as prior experience, fitness level, level of motivation, and natural variations in physiological and behavioral processes across the 24-h cycle (100, 101). The SCN in the hypothalamus regulates these circadian cycles (102). Humans are extremely sensitive to changes in their natural environment, especially through the light–dark cycle, but the SCN cannot always maintain full control over these patterns (94).

Sleep is a recurrent, brief, and highly functioning state governed primarily by neurological mechanisms. Insomnia and other sleep disorders are increasingly identified in people of all ages. Sleep disorders are risk factors for depression, mental illness, heart disease (103), metabolic syndrome, and high blood pressure (104). Stress, anxiety, stimulant use, and exposure to electronic devices before bedtime are all known to diminish the quality of sleep (105). Increasing research suggests that diet, physical activity, and good sleeping habits can exert major influences on how well one sleeps (106). Tsunoda et al. reported that people who lead active lives sleep better and for longer than their sedentary counterparts. The quality of sleep can be improved without the use of pharmaceuticals if we increase our daily physical activity, outdoor exposure, and participation in activities such as walking (107). Moreover, in adults, regular exercise improves sleep quality when practiced over time. Increasing one's activity time and step count leads to better sleep, thus reinforcing the idea that any form of physical exercise is better than none (21). Jannsen et al. found in a recent review that infants with higher total physical activity levels tend to have shorter sleep durations and fewer naps during the day (108). Nevertheless, children and preschoolers with higher daily activity levels report better sleep quality and more consistent sleep patterns, suggesting that physical activity improves sleep (108). The quality of sleep is also influenced by the intensity of exercise. For example, preschoolers who engage in mild forms of physical activity tend to stay up later at night (109). Moreover, 73% out of 91 adolescents (11–19 years old) in Fairbrother et al.’s study reported problems staying asleep, and 65% had trouble falling asleep (110). Regular moderate-to-strong exercise is correlated with later bedtimes and shorter total sleep durations. In contrast, children between the ages of one and three who engage in more physical activity have improved sleep quality, fall asleep faster, and have fewer nighttime awakenings (108).

As already observed, physical exercise may affect our ability to sleep, but there is a reverse scenario where sleep disorders affect athletic performance and regular physical activity habits (Figure 1) (6). Endogenous circadian rhythms and typical sleep–wake cycles can become desynchronized. When individuals go to bed later than usual or get up earlier than usual, this is termed sleep restriction (SR). On the other hand, SD is the result of chronic sleep loss in which a person obtains little or no sleep for an extended period (i.e., many nights) (111). Findings by Mougin et al. indicate that SR increases physiological demand during athletic performances, leading to fatigue in athletes at a faster rate than normal (112). It appears that submaximal strength, muscular power (40), and anaerobic power all decrease after SR (45, 113). While these results suggest that SR hinders several aspects of sports performance, it remains unclear if sleep is crucial to performance in all athletes who experience brief, one-time spells of SR. However, poor sleep quality and quantity can trigger an imbalance in the autonomic nervous system (ANS), mimicking the overtraining condition. Sleep deprivation has been linked to an increase in proinflammatory cytokines, which may contribute to immune system malfunction. Furthermore, many studies have found that cognitive functioning slows down and becomes less accurate when people do n't get sufficient sleep (6). In addition, although sufficient data suggest that SD can have a major effect on aspects of athletic performance (54), the exact effect of SD on exercise performance is unclear (114, 115). This is especially relevant for the amount of time it takes to become completely exhausted while running for longer than 30 min (116). However, Symons et al. found no difference between SD participants and a control group on several maximum isometric and isokinetic strength tests for the upper and lower body after 60 h. Several studies have confirmed that one's grip strength performance does not decline with time spent awake (114). Nevertheless, Skein et al. noted that after 30 h of SD, 10 team sport athletes experienced slower mean sprint speeds, decreased muscle glycogen concentration, lower voluntary force and activation during maximal isometric knee extensions, and an increase in perceptual effort (54).

Both SD and SR may arise due to many factors in athletic contexts, such as travel schedules or training/playing at night (117). Sleep disruptions can increase homeostatic pressure, as well as have effects on emotional control, core temperature, and circulating melatonin, thereby delaying the onset of sleep. After many such occurrences, sleep deprivation and impaired cognitive and physiological functioning may set in (118). Erlacher et al. reported that while many athletes claimed that sleep disruption had little effect on their performance, others noted negative side effects such as a bad disposition the following day (119). Furthermore, 15% of the athletes reported experiencing nightmares in the 12 months prior to a major competition or game (120). Lastella et al. found that approximately 70% out of 103 athletes experienced poorer sleep than usual on the night before a competition, falling well below the recommended 8 h of sleep for healthy adults. Common reasons included nerves, noise, toilet breaks, and early start times (121). However, some studies reported that there was no significant shift in heart rate variability or other measures of autonomic nervous system activity among top female athletes in team sports just before a big game (122). In contrast, Edmonds et al. observed reduced parasympathetic and/or primary sympathetic modulation in athletes prior to a game, with their autonomic responses to standing dramatically reduced during and after the game for up to 4 days (123).

Although sleep is widely acknowledged to be important for human and athletic performance, the literature remains divided on whether or not a lack of sleep leads to a reduction in actual, measurable performance (124). Athletes may experience sleep deprivation right before a competition or if they are required to exercise at unusually early hours, but there is less proof of this happening in team sports (125). Contradictory evidence exists for the effect of acute SR. Performance during maximal one-off efforts (in particular for maximal strength) is generally maintained, but SD appears to have a negative impact on exercise performance (particularly endurance and repeated exercise bouts) (6).

Sleep is a fundamental human behavior that plays a crucial role in biopsychosocial development and has significant implications for biological, physical, psychological, and cognitive health (126). Although research in this area remains limited, empirical studies focusing on sleep in professional athletes have increased in recent years. Sleep health has a profound impact on various dimensions of professional athletics, including training, injury risk, recovery, and actual performance.

The mechanisms regulating sleep have an impact on the gene expression of the central nervous system (CNS) and involve the endocrine, immune, and energy regulation systems. Sleep is determined by the activation of the SCN, which integrates information from all parts of the organism (151). This suprachiasmatic nucleus–hypothalamus axis regulates the sleep–wake cycle at the molecular level through a constant maintenance of energy by circadian fluctuations of enzymes involved in tissue metabolism (152). It is known that the circadian rhythm of sleep is generated through different feedback processes that are determined by the amount of ambient light on circadian genes within SCN cells (153, 154).

All information is integrated in the nuclei of the hypothalamus, allowing interaction between the anterior and posterior hypothalamus, the brainstem, and the basal forebrain, where the most essential neuromodulators in mammals are located, and which project to a large part of the olfactory system and the cerebral cortex (155). REM–NREM sleep cycles are regulated by the ultradian oscillator of the mesopontine junction and the transition between these cycles is modulated by the locus ceruleus and the nucleus oralis pontis reticularis (156). During non–rapid eye movement sleep (NREM) sleep, a decrease in sympathetic activity is evident, reducing overall activity of the organism. In contrast, REM sleep is associated with neuronal repair actions, including memory consolidation, synaptic homeostasis, brain maturation, and learning (157).

All this is also consistent with other mechanisms that are coordinated by the light–dark cycle, such as thermogenesis, glucose metabolism, intake, and lipid levels, which present modulations due to alterations in this circadian pattern (158). Therefore, when the quality and quantity of sleep are not adequate, different organic pathologies appear, such as alterations in insulin sensitivity and glucose tolerance, which are risk factors for developing diabetes, obesity, metabolic syndrome, and other diseases (159, 160).

Sleep has been directly linked to physical activity. The study of this field has seen increased interest in recent years, given the evidence of similar sleep patterns in patients with pathologies such as obesity, diabetes, or insulin resistance (161). Recent studies have shown that alterations in sleep patterns increase the expression of the antioxidant enzymes Glyoxalase-1 and Glutathione reductase, while increasing oxidative stress in the hippocampus, amygdala, and cerebral cortex (162). Moreover, physical activity and sleep are governed by distinct yet interconnected homeostatic physiological mechanisms that interact to facilitate sleep during periods of reduced light exposure. These mechanisms activate the somnogenic regions in the brain by lowering body temperature to prepare the organism for sleep induction (104).

Physical activity is closely associated with the regulation of ultradian cycles, whose activity decreases in the early afternoon. Physical exercise should be performed at a time that favors endogenous rhythms, considering the type of activity to be performed and individual factors, but ideally 4–5 h before going to sleep (163). Electroencephalogram (EEG) recordings show that individuals who perform regular physical activity exhibit slow brain wave activity across all sleep cycles. On the contrary, people with low or no physical activity presented less slow brain wave activity in addition to a greater predisposition to present depressive symptomatology. This indicates that these processes are interrelated and that these two systems work together to maintain organic homeostasis (164–166).

Sleep is also related to hormonal regulation. In relation to the immune system, proinflammatory cytokines are in charge of modulating sleep and their activity is altered with sleep deprivation (69, 167). Modifications of sleep–wake patterns have been observed in conditions such as fibromyalgia, major depressive disorder, or infectious diseases, directly impacting the immune system. Sleep is associated with the expression of T cells and the proinflammatory cytokines such as TNF-α and IL-6, which rise in the presence of sleep disturbances (168). In addition, the expression of cell adhesion molecules Mac-1 and L-selectin on lymphocytes and monocytes shows alterations in the circadian rhythm and its periodicity, linked to the modulation of leukocyte-induced pathogenesis of asthma or cardiovascular crises and strokes (169).

Different sleep cycles have an impact on glucose and insulin secretion, with hypoglycemia sometimes occurring at night. Glucose metabolism intensifies its activity through the influence of the SCN, which prepared the body for awakening and increased activity (170). Maintaining the circadian rhythm supports the proper circulation of afferent and efferent signals and protects against ANS dysfunctions such as diabetes or metabolic syndrome (171). Low melatonin levels promote insulin sensitivity, reduce blood pressure during sleep, and flattened melatonin rhythms (172).

Sleep dysfunction induces an increase in cortisol levels in the late afternoon, leading to very high amounts of glucocorticoids (101). During the physiological processes underlying the initiation of slow-wave brain activity, cortisol tends to be inhibited, and during this sleep period, orexins regulate food metabolism and energy balance as well as reward mechanisms, so that sleep restriction for one night is sufficient to affect leptin levels the next morning as well as cortisol rhythms (173).

In relation to neuronal pathways, the connections between these specialized cells are maintained during the sleep cycle. During this period, they assume the function of maintenance and repair, which allows the elimination of toxins that are stored throughout the day (174). As the day comes to an end, chemical signals moderate neuronal activity, inducing sleep (175). GABA or γ-aminobutyric acid is a neurotransmitter that acts as the main inhibitor of the CNS; in addition to other functions, and once it is activated, it blocks the transmission of information from motor neurons, favoring the reduction of excitation (176). On the other hand, norepinephrine and orexin are responsible for maintaining neuronal activity in certain regions of the brain during wakefulness. Other neurotransmitters such as acetylcholine, adrenaline, serotonin, and histamine are also present (177, 178).

The brainstem and the ascending reticular activating system are essential for cortex stimulation, particularly in the region of the posterior hypothalamus since this is where the waking state is maintained (179). With the release of glutamate, the cortex is activated via the dorsal pathway and the ventral pathway of the hypothalamus, projecting to the cerebral cortex and hippocampus (180). During sleep, the cerebral cortex and the thalamus interact. There are two neuronal circuits in the brainstem that act alternatingly to induce sleep or wakefulness; they are composed of reduced neuronal groups that form very complex circuits in a structural network to maintain homeostasis (181).

There are other brain regions that are involved in sleep modulation. According to recent studies, the area known as the pons sends signals to the thalamic nuclei and the cortex and communicates with the spinal cord to temporarily block motor activity (182). In addition to the reticular activating system, researchers have investigated whether the nucleus of the solitary tract, which is in the dorsal medulla, could create a link between the sleep–wake state and cardiovascular, respiratory, and gastrointestinal functions (183). Although it has no direct projection to the cortex, it does project to areas of the brainstem, thalamus, and hypothalamus, thereby reaching the cortex by innervation and modulating waves during sleep (184).

Individual differences in digestive and metabolic processes account for a large portion of the observed variability in dietary variables. In addition, hormones and inflammatory states can be directly or indirectly affected by nutrition, both of which contribute to sleeplessness. Although the role of diet in controlling sleep is multifaceted (185), several possible explanations have been proposed. To begin, certain parts of one's diet can have an immediate effect on one's ability to rest (186). In addition, the inflammatory status, which is also closely associated with sleeplessness, may be changed by long-term dietary changes (187). Numerous studies have demonstrated that sleep disruption is linked to increased levels of glucocorticoid and decreased levels of inflammatory cytokines (particularly C-reactive protein and interleukin 6) (104). Melatonin is a well-known sleep aid that informs the body about when it should be dark and when it should be light. The effects of melatonin on sleep and circadian rhythm are mediated by two G-protein-coupled receptors, MT1 and MT2. Thus, melatonin-containing foods have an effect on sleep quality (188).

Within this broader lifestyle context, recent evidence has emphasized the integrative role of chronotype and physical activity in shaping sleep and dietary behaviors. Evening chronotypes appear more vulnerable to poor sleep quality, whereas shifts toward a morning chronotype are associated with marked improvements in sleep quality alongside distinct dietary patterns, underscoring the interconnected nature of sleep, physical activity, chronotype, and nutrition (189).

The potential synergies between physical activity, sleep, and nutrition interventions have garnered increasing attention in recent years, with numerous studies exploring the interconnectedness of these lifestyle factors. The interplay between physical activity and sleep has been investigated in several studies. For instance, Chaput et al. (213) conducted a study involving adults and found that higher physical activity levels were associated with improved sleep duration and quality. These findings are supported by Sanz-Martín et al. (214), who reported a positive correlation between physical activity and sleep duration among adolescents. Similarly, it has been demonstrated that regular physical activity was linked to decreased sleep latency and increased sleep efficiency. These studies collectively suggest that engaging in physical activity may positively influence sleep patterns. Moreover, the timing of exercise in relation to sleep has been explored. Youngstedt et al. (5) found that engaging in moderate-intensity aerobic exercise in the morning led to improved sleep quality. In contrast, evening exercise was associated with prolonged sleep latency (5). These findings highlight the importance of considering exercise timing when examining the relationship between physical activity and sleep.

In terms of nutrition and sleep, the influence of macronutrient composition on sleep quality has been investigated. Afaghi et al. (215) observed that a higher carbohydrate intake was associated with improved sleep quality and decreased sleep onset latency. Similarly, St-Onge et al. (167) reported a positive correlation between carbohydrate consumption and sleep efficiency (216). In addition, protein intake has been implicated in sleep outcomes. Higher protein intake has been linked to fewer awakenings during sleep (215). These findings suggest that dietary choices, particularly the consumption of carbohydrates and protein, may impact sleep quality. Micronutrient deficiencies have also been associated with sleep disorders. Grandner et al. (217) highlighted that deficiencies in iron, magnesium, and vitamin D were linked to an increased risk of sleep disorders. Similarly, Gao et al. (199) reported an association between low vitamin D levels and poor sleep quality. Ensuring adequate intake of these micronutrients through a balanced diet or supplementation may potentially improve sleep quality.

Integrating interventions targeting physical activity, sleep, and nutrition may yield synergistic effects on various health outcomes. Mikkelsen et al. (218) conducted a study that examined the effects of a combined intervention on mental health. They found that a 12-week combined intervention significantly reduced symptoms of depression and anxiety compared to single-component interventions. This suggests that addressing multiple lifestyle factors simultaneously may yield greater mental health benefits. Furthermore, combined lifestyle interventions encompassing physical activity, sleep, and nutrition components have shown promise in improving metabolic health and reducing chronic disease risk factors. For example, it was reported that a combined lifestyle intervention led to greater improvements in insulin sensitivity and lipid profiles compared to individual interventions targeting only one lifestyle factor (219).

Sleep assessment has gained significant attention in recent decades, leading to the development and incorporation of various devices to evaluate sleep quality. PSG is widely recognized as the gold standard for assessing sleep since its introduction in clinical practice in 1974 (220). PSG is a comprehensive technique that involves the simultaneous monitoring of multiple dimensions of sleep. Typically, a PSG recording includes measurements of central, frontal, and occipital EEG activity, eye movements, chin and other muscle activity (EMG), electrocardiogram, pulse oximetry, respiratory efforts, nasal and oral airflow, and body position (220). Depending on individual needs and conditions, PSG can be complemented with additional sensors, allowing for a more detailed evaluation of sleep patterns and characteristics (221).

Although PSG provides the most accurate and comprehensive assessment of sleep, it is a complex, expensive, and time-consuming procedure (222). It requires trained technicians to set up the equipment and specialized expertise to analyze the collected data. Consequently, self-reported sleep measures have been widely used as a more accessible alternative for assessing sleep quality. Sleep diaries and questionnaires, for instance, offer subjective estimations of various sleep-related parameters and are commonly employed for initial screening of sleep disorders (7). Several questionnaires have been developed specifically for sleep assessment, including the Karolinska Sleep Diary (223), the Pittsburgh Sleep Quality Index (PSQI) (224), the Epworth Sleepiness Scale (225), and the Sleep Hygiene Index (226), as well as questionnaires tailored to athletes such as the Athlete Sleep Behavior Questionnaire (227) and the Athlete Sleep Screening Questionnaire REF (228). These instruments provide valuable insights into subjective sleep experiences and can serve as effective screening tools for identifying potential sleep issues.

Another objective method for assessing sleep/wake behavior, particularly in certain populations, is actigraphy. Actigraphy has gained popularity as a reliable alternative to PSG. Actigraphic devices typically include triaxial (3D) or biaxial (2D) accelerometers that record movement patterns over time. Through specific algorithms, these devices estimate sleep/wake behaviors based on activity levels. Actigraphy indirectly measures sleep by analyzing individuals' motor activity levels, assuming that fewer movements occur during sleep (134). Various sleep parameters—such as total sleep time, SOL, SE, and WASO—can be derived from the wakefulness/sleep data collected by actigraphy (134). Actigraphy offers a convenient and practical method for objectively measuring sleep in both athletes and non-athletes. It is more affordable than PSG, requires less expertise in device setup and data analysis, and allows for long-term sleep monitoring. Actigraphy can be performed in participants' habitual sleep environments, such as their own homes and bedrooms, with minimal discomfort.

The market for consumer wearable devices has experienced remarkable growth, providing individuals with the means to monitor their physical activity, sleep, and other behaviors (229). The growing interest in sleep among the general population has been facilitated by the introduction of commercial wearables and nearables designed for sleep tracking. Wearable technology refers to electronic devices and systems integrated into clothing or worn on the body (230). Smartwatches, GPS-enabled sneakers, and wristbands are examples of wearable devices that have become increasingly popular. These devices offer a combination of user-friendly features and affordability, allowing for simple and long-term sleep monitoring. They do not require expertise as most of them do not export raw data but utilize proprietary algorithms to analyze and interpret the collected data. These devices are typically connected to remote applications that directly display the results (229). Dedicated sleep trackers have emerged as a niche within the wearable market. These devices focus solely on monitoring sleep-related metrics and are designed to be worn during the night. They employ a combination of sensors—such as accelerometers, gyroscopes, and sometimes even ambient light sensors—to capture detailed information about sleep duration, sleep stages, and sleep interruptions. Some sleep trackers also offer features like snore detection and analysis of sleep positions. Moreover, wearable devices in the form of rings have also entered the sleep tracking market. These rings are worn on the finger and utilize various sensors, such as pulse wave sensors, to gather data on sleep patterns. The compact design of these rings allows for unobtrusive and comfortable sleep monitoring. To analyze and interpret the data collected by wearable devices, manufacturers typically provide companion mobile applications or web platforms. These applications display sleep metrics, generate sleep reports, and offer insights into sleep patterns over time. Many of these platforms leverage machine learning algorithms to provide personalized recommendations for improving sleep quality.

In recent years, there has been a growing interest in developing personalized interventions to optimize sleep and physical activity habits. Personalization is crucial because individuals vary in their sleep patterns, activity levels, preferences, and behaviors. By tailoring interventions to meet the specific needs and characteristics of individuals, it is possible to enhance the effectiveness and engagement of interventions aimed at improving sleep and physical activity. Research has explored the use of personalized interventions in the context of sleep and physical activity. Ghanvatkar et al. (231) conducted a scoping review on personalized physical activity interventions, highlighting the importance of considering individual variations in activity levels, requirements, preferences, and behavior when designing interventions. Personalized approaches were shown to promote and sustain physical activity behaviors. Furthermore, a study by Shimamoto et al. (232) investigated the effectiveness of brief personalized interventions for improving physical activity and sleep among older adults. The study utilized mHealth strategies—including self-monitoring, motivational messages, activity reminders, and phone coaching—to facilitate participation and engagement in physical activity. The findings suggested that personalized interventions delivered through mobile health platforms have the potential to positively impact both physical activity and sleep behaviors.

Recent research has demonstrated the effectiveness of personalized interventions in improving sleep outcomes and physical activity levels. For example, a recent systematic review showed how physical activity programs have positive effects on sleep outcomes, particularly in the adolescent population (233). Another study by Ghanvatkar et al. (231) highlighted the importance of personalization in mobile health interventions aimed at increasing physical activity. These findings emphasize the need for tailored approaches to address sleep and physical activity habits. Moreover, combining interventions targeting both physical activity and sleep quality has shown promise in improving overall health outcomes. In another study, the authors implemented a mobile health combined behavior intervention focusing on physical activity and sleep quality, which resulted in positive changes in participants' behaviors (234). This suggests that personalized interventions addressing both domains can lead to more comprehensive and effective outcomes.

A randomized controlled pilot trial investigated the preliminary effect of a 24-week mHealth-facilitated personalized intervention on physical activity and sleep in community-dwelling older adults. The intervention included personalized exercise prescription, training, goal setting, and financial incentives, with the incorporation of mHealth strategies such as self-monitoring, motivational messages, activity reminders, and phone coaching. The study found positive outcomes in terms of improving physical activity levels and sleep quality among the participants (235). Another scoping review found that personalized goal setting and daily logging with dynamic feedback improved overall sleep quality, subjective sleep quality, sleep onset latency, wake-time variability, sleep hygiene, and insomnia severity (236).

In another study where authors reviewed the relationship between sleep and physical activity and their impact on human health, they proposed several physiological mechanisms between sleep and exercise, including the influence of physical activity on sleep quality and duration, as well as the effects of sleep on physical activity performance and recovery. There is also a bidirectional relationship between sleep and physical activity, suggesting that those with sleep disorders may benefit from engaging in increased physical activity (237). A systematic review of the interrelationship between sleep and exercise showed that higher leisure-time physical activity was correlated with better sleep, suggesting that engaging in leisurely physical activity can improve sleep quality. Conversely, the authors also suggested that the relationship between sleep disorders and physical activity is bidirectional, with sleep disorders resulting in greater fatigue throughout the day, thus lowering the likelihood of exercising (19). Another scoping review examined the effect of various physical activity intervention strategies on sleep across different populations. The review found that personalized goal setting and daily logging with dynamic feedback can improve overall sleep quality, subjective sleep quality, sleep onset latency, wake-time variability, sleep hygiene, and insomnia severity. Other intervention programs—including behavioral feedback, goal setting, or health coaching programs—provided behavioral support to improve adherence through phone contact, email connect, or group sessions (238).

Collectively, these studies provide valuable insights into the potential benefits of personalized interventions for optimizing sleep and physical activity habits. By considering individual characteristics and tailoring interventions accordingly, it is possible to enhance intervention outcomes and promote healthier sleep and activity behaviors.

Future research in the field of sleep and physical activity should focus on several key areas to expand knowledge and provide comprehensive insights into this complex interplay. The following lines of research are suggested:

Longitudinal studies: Examine the bidirectional relationship between sleep and physical activity over extended periods. This will help establish causal relationships and determine how changes in one behavior influence the other over time.

This narrative review highlights the complex and dynamic bidirectional relationship between sleep and physical activity, emphasizing their joint relevance as modifiable lifestyle behaviors with profound implications for physical, metabolic, and mental health. The evidence consistently indicates that regular physical activity, particularly at moderate intensity, is associated with improvements in sleep quality, while adequate sleep duration and quality are essential for optimizing physical performance, recovery, and long-term engagement in physical activity. Importantly, these relationships are not linear but are shaped by multiple interacting factors, including exercise timing, intensity, chronotype, nutritional habits, and individual characteristics.

Despite a robust body of evidence supporting the beneficial effects of physical activity on sleep quality, important inconsistencies remain—particularly regarding sleep duration, high-intensity exercise, and evening training. Much of the current literature is observational, limiting causal inference, and intervention studies often focus on short-term outcomes in relatively homogeneous adult populations. Consequently, key gaps persist concerning population-specific responses, sex differences, long-term adherence, and interindividual variability in responsiveness to exercise-based sleep interventions.

This review also underscores the integrative role of nutrition and chronotype in shaping sleep–physical activity interactions, reinforcing the need to move beyond isolated behavioral approaches. Emerging evidence suggests that combined lifestyle interventions targeting sleep, physical activity, and dietary patterns may yield synergistic benefits for metabolic health, mental wellbeing, and disease prevention. In this context, advances in wearable technology and digital health tools offer promising opportunities to monitor sleep and physical activity objectively, support personalized interventions, and improve long-term adherence.

Future research should prioritize well-designed longitudinal and randomized controlled studies that incorporate objective measurements, diverse populations, and sufficient follow-up durations to clarify causal pathways and optimize intervention design. Embracing personalized, chronobiologically informed, and multisystem approaches will be essential to translating the growing body of evidence into effective, scalable strategies for improving sleep health, physical activity engagement, and overall wellbeing.