Why Do Happy People Exercise More? The Role of Beliefs in the Psychosocial Benefits of Exercise

“It is exercise alone that supports the spirits and keeps the mind in vigor.”

– Marcus Tullius Cicero.

The scientific literature provides extensive evidence of the myriad benefits of exercise (Penedo et al., 2005). Exercise not only safeguards physical well-being (Rebelo-Marques et al., 2018) but also promotes emotional (Smith & Merwin, 2021), cognitive (Mandolesi et al., 2018) and social well-being (Opstoel et al., 2020). In terms of physical well-being, regular exercise is beneficial for muscular strength (Platta et al., 2016) and the cardiovascular system (Nystoriak & Bhatnagar, 2018), to name a few. Concerning psychosocial well-being, exercise increases life satisfaction and positive emotions (Zhang & Chen, 2019) while decreasing negative emotions and stress (Smith & Merwin, 2021). In fact, health and psychology professionals have touted exercise as a highly effective skill for emotion regulation (Bernstein & McNally, 2018). Moreover, exercise confers significant cognitive benefits—including enhancements in memory (Roig et al., 2013), creativity (Rominger et al., 2022), attention, and academic performance (Spitzer & Hollmann, 2013). Last but not least, exercise enhances social well-being by fostering social interactions (Di Bartolomeo & Papa, 2019) and encouraging the exercise habits of close relationships (Darlow & Xu, 2011). In short, it can be argued that exercise is close to a panacea.

Yet, a significant portion of adults (27%) and adolescents (80%) globally fail to meet the minimum physical activity guidelines established by the World Health Organization (WHO, 2022). Even more striking is that those who could benefit the most—namely, unhappy individuals—often exercise the least. Existing studies suggest that individuals with lower levels of subjective well-being (SWB; Diener, 1984)—encompassing both cognitive (life satisfaction) and affective components (positive versus negative affect)—are less likely to engage in a range of health-promoting behaviors, including but not limited to exercise. For example, an analysis of data from 1.5 million people across 166 countries revealed that higher SWB is associated with increased exercise (Diener et al., 2018). Supporting this, findings from another large-scale survey of 2.5 million Americans identified positive affect and life satisfaction as key predictors of physical activity (Kushlev et al., 2020). Evidence from more fine-grained methods, such as experience sampling methods and accelerometer data, further demonstrates that higher SWB not only predicts current exercise habits but also correlates with future physical activity levels (Lathia et al., 2017). Moreover, longitudinal studies indicate that greater life satisfaction encourages sports participation over time (Frey & Gullo, 2021), while experimental research underscores the role of positive affect in fostering more favorable attitudes toward exercise (Catellier & Yang, 2013).

The disparity in exercise levels between happy and unhappy individuals poses the crucial yet elusive question of why this difference occurs (Steptoe, 2019; Zhang & Chen, 2019). While various factors could contribute to exercise behavior—such as differences in motivation (e.g., Ng et al., 2012), social support (Carron et al., 1996), or accessibility (Duncan et al., 2005)—the present work aims to address this inquiry by focusing on beliefs about exercise benefits. This focus is supported by existing theoretical and empirical studies that demonstrate that individuals who perceive greater benefits from exercise are more likely to form intentions to exercise and actually participate in exercise (Ajzen, 1985; Bandura, 1986; Becker & Maiman, 1975; Carpenter, 2010; Pender et al., 2006) and happiness can be an antecedent for these beliefs (e.g., Ajzen, 2011; Kavanagh & Bower, 1985). Building on this premise, the study proposes that beliefs about exercise benefits may account for the disparity in exercise levels between individuals with higher and lower SWB. More importantly, we argue that the difference in beliefs about exercise benefits between happier and less happy people would be larger in the psychosocial (i.e., exercise is beneficial for one’s mental and social health) than the physical benefits (i.e., exercise is beneficial for one’s physical health). Ultimately, we hypothesize that psychosocial benefits play a more substantial role than physical benefits in explaining the relationship between SWB and exercise.

Individuals hold beliefs about the benefits of exercise (hereafter, exercise benefit beliefs). Since informal notions about the world are not always aligned with facts (Furnham, 1988), some may disagree with certain scientifically confirmed benefits of exercise, while others may attribute even greater significance to these benefits. Exercise benefit beliefs consistently emerge as strong predictors of exercise behavior across various theoretical frameworks, despite variations in terminology (see Carpenter, 2010 for a review). For instance, the Theory of Planned Behavior (TPB) emphasizes “perceived benefits,” along with enjoyment and perceived control, as critical for shaping exercise intentions and behaviors (Ajzen, 1985). Similarly, the Social Cognitive Theory (SCT) highlights “expected outcomes” and self-efficacy as central to behavior change (Bandura, 1986). Beyond general behavior theories like TPB and SCT, health-specific models such as Health Promotion Model (HPM) and Health Belief Model (HBM) reinforce these ideas. The HPM identifies “perceived benefits” as a primary motivational factor alongside perceived barriers (Pender et al., 2006), while the HBM underscores the “perceived effectiveness of exercise” as a driver of physical activity (Becker & Maiman, 1975). Collectively, these models advocate that individuals with stronger exercise benefit beliefs are more likely to engage in regular physical activity. Based on this theoretical foundation, we propose that happier individuals perceive greater exercise benefit beliefs.

We take a further step by elucidating how exercise has been extensively studied for its multifaceted benefits, spanning both physical and psychosocial domains. Physical benefits encompass improved cardiovascular health (Nystoriak & Bhatnagar, 2018) and increased strength (Platta et al., 2016), while psychosocial benefits include enhanced mood (Smith & Merwin, 2021), better cognitive functions (Mandolesi et al., 2018), and improved social interactions (Opstoel et al., 2020). While existing research consistently underscores the importance of exercise benefit beliefs as a strong predictor of exercise behavior, studies did not yet clearly distinguish between physical and psychosocial dimensions of exercise benefits. To address this gap, the present study explicitly differentiates between these two dimensions in the context of exercise benefit beliefs. Physical benefit beliefs focus on tangible advantages, such as athletic performance and rehabilitation, while psychosocial benefit beliefs emphasize less tangible aspects, including emotional, cognitive, and social well-being. Existing scales, such as the Exercise Benefits/Barriers Scale (EBBS; Sechrist et al., 1987), grounded in the HPM, and the Multidimensional Outcome Expectations for Exercise Scale (MOEE; Wójcicki, 2009), rooted in the SCT, provide a foundation for this distinction. The EBBS identifies physical performance (e.g., increased muscle strength) and preventive health benefits (e.g., heart attack prevention), consistent with physical benefit beliefs, alongside psychological outlook (e.g., improved mental health), life enhancement (e.g., better work quality), and social interaction benefits (e.g., meeting new people), which align with psychosocial benefit beliefs. Similarly, the MOEE differentiates physical (e.g., increased muscle strength), social (e.g., improved social acceptance), and self-evaluative (e.g., enhanced mood) benefits, with the latter two resonating with psychosocial benefit beliefs. However, these scales do not explicitly categorize benefits in this manner.

Although previous research has not clearly differentiated between physical and psychosocial benefits in the context of exercise behavior, comparing the two factors offers not only conceptual but also empirical values. Empirical research suggests that individuals evaluate the psychosocial and physical benefits of exercise differently. On the one hand, individuals typically underestimate the emotional benefits of exercise (e.g., increased feelings of enjoyment) that they would experience after a workout (Ruby et al., 2011). Similarly, those with lower physical activity levels reported significantly weaker beliefs in the social benefits of exercise (e.g., building social interaction), with a mean score of 2.5 out of 4, compared to physical benefits, with a mean score of 3.25 (Lovell et al., 2010). On the other hand, empirical studies consistently demonstrate that emphasizing psychosocial benefits is more effective in promoting exercise intentions than focusing solely on physical outcomes (see Williamson et al., 2020 for a review). For example, highlighting the emotional benefits of exercise (e.g., improved mood) significantly boosts exercise intention, compared to physical benefits, particularly among less active individuals (Hevel et al., 2019).

Accordingly, even though direct empirical comparisons of the predictive power of these beliefs remain scarce, existing theoretical and empirical investigations suggest that psychosocial benefit beliefs may be stronger predictors of exercise intention and behavior. Physical benefits, despite being intuitive and widely acknowledged, may exert less variability in their motivational impact due to their universal acknowledgment. In contrast, psychosocial benefits, while being less tangible, are subject to greater individual differences in belief strength and salience. We lend this evidence to investigate how beliefs about psychosocial benefits, compared to physical benefits, more strongly inspire individuals’ motivation to engage in exercise.

How do happier people differ from less happy people in their physical and psychosocial benefit beliefs regarding exercise? The present research proposes that the gap between these groups stems from differences in exercise benefit beliefs, with a particularly pronounced disparity in psychosocial benefits. This proposition is grounded in theoretical frameworks and empirical evidence on how SWB influences distinct cognitive processing styles and behavioral tendencies between happier and less happy individuals.

From a theoretical standpoint, positive emotions—one of the key components of SWB—play a crucial role in shaping individuals’ cognitive and behavioral processes. The affect-as-information model posits that positive affect influences how individuals appraise situations, often acting as heuristic cues for interpretation (Schwarz & Clore, 1983). Exercise is likely no exception to this process. The distinct cognitive patterns of happier and less happy individuals likely shape their different interpretations of the same exercise activity. Happier individuals, for instance, employ exercise as a happiness-boosting behavior (Tkach & Lyubomirsky, 2006), suggesting that they view exercise not only as a means of improving physical health but also as a way to enhance emotional well-being.

The broaden-and-build model further elucidates how positive emotions expand individuals’ thought-action repertoires (Fredrickson, 1998, 2001). According to this model, happiness encourages exploratory behaviors that build enduring mental resources. This implies that positive emotions enable individuals to appreciate the broader, more nuanced aspects of behaviors by encouraging engagement in diverse activities, including exercise. For instance, happier individuals may seek to enhance their psychosocial well-being by exploring novel and diverse activities, including exercise, even if the psychosocial benefits are not immediately tangible. This intentional exploration may allow them to recognize the psychosocial benefits of exercise, leading them to adopt it as a routine. Accordingly, existing theories suggest that happier individuals could develop unique cognitive patterns when it comes to activities such as exercise, shaping their exercise benefit beliefs differently.

This idea is further supported by empirical studies demonstrating that SWB fosters distinct cognitive processes, which may permit happier individuals to recognize not only the physical benefits but also the psychosocial benefits of exercise. Individuals with higher levels of positive mood employ a global processing style (Isbell, 2004), meaning that they consider the long-term benefits of their experiences. For instance, people underestimate how much they enjoy exercise due to a myopic focus on the initial discomfort or unpleasantness of starting exercise (Ruby et al., 2011). In contrast, happy individuals, with their global processing style, may be better able to downplay the initial burdens associated with exercise, such as pre-workout inertia or physical discomfort during the activity; instead, they could emphasize the sense of accomplishment tied to physical improvements, the emotional uplift following exercise, or the strengthened social bonds resulting from group activities. This long-term perspective enables them to view exercise as a holistic contributor to their overall well-being.

Furthermore, individuals with greater levels of SWB believe that happiness is malleable and can be cultivated through effort. This belief is strongly associated with traits such as optimism, perceived personal control, and self-efficacy, all of which are closely linked to SWB (Lucas et al., 1996; Lyubomirsky et al., 2005; Van Tongeren & Burnette, 2018). Research also demonstrates that this belief motivates participation in happiness-promoting activities, such as physical exercise (Choi et al., 2021). Integrating these findings, it stands to reason that happier individuals who view happiness as something that can be intentionally developed are more likely to pursue activities they associate with enhancing their psychosocial well-being. Indeed, they are inclined to view exercise not merely as a physical activity but also as a strategic tool for cultivating psychosocial benefits (Tkach & Lyubomirsky, 2006). It is inferrable that their belief in the malleability of happiness may heighten their recognition of the psychosocial benefits of exercise, which enhances their motivation to engage in exercise.

The unique cognitive and behavioral mechanisms of happier individuals explain why they could hold not only physical but also psychosocial benefit beliefs more, contrasting with less happy people who might focus less on intangible outcomes. Thus, we propose that happier people believe in more exercise benefits, with the disparity between happier and less happy individuals being larger in psychosocial than physical benefits. Given the stronger relationship between psychosocial benefits and exercise behavior (e.g., Williamson et al., 2020), we can further speculate that psychosocial benefit beliefs more strongly mediate the relationship between happiness and exercise, compared to physical benefit beliefs.

Although previous research has consistently shown that SWB influences exercise benefit beliefs, some may argue that SWB is often conceptualized as an outcome of behavior. However, ample evidence suggests SWB can also function as an antecedent (Choi & Choi, 2017; Lyubomirsky et al., 2005). SWB predicts a range of proactive behaviors, including voting, saving, participating in social activities, and engaging in hedonic spending (Flavin & Keane, 2012; Guven, 2012; Sul et al., 2013; Zhong & Mitchell, 2012). SWB also contributes to the formation of beliefs, serving as a predictor. According to frameworks like the TPB and SCT, beliefs are central determinants of intention and behavior, and they are shaped by correlates of well-being, such as mood and affect. TPB posits that exercise benefit beliefs influence exercise intentions (Downs & Hausenblas, 2005; Godin & Kok, 1996); importantly, background factors play a critical role in shaping these beliefs. To illustrate, general mood, as a key background factor, can influence beliefs’ strength and evaluation, while affective states determine the accessibility of specific beliefs (Ajzen, 2011). Within this framework, SWB can influence beliefs, which in turn shape exercise intention. The SCT further champions this idea, demonstrating the impact of exercise benefit beliefs on behavior (see Beauchamp et al., 2019 for a review), with personal factors modulating this dynamic (e.g., Kavanagh & Bower, 1985). It indicates that personal factors like positive moods enhance exercise benefit beliefs, thereby reinforcing exercise behavior. This empirical and theoretical framework potentially advocates for our premise that happiness is a precursor to exercise benefit beliefs, ultimately impacting exercise intention and behavior.

This research intends to present and empirically test two core hypotheses. First, we hypothesize that happier individuals will exhibit stronger beliefs about both physical and psychosocial benefits of exercise, with a more pronounced effect of psychosocial benefit beliefs (Hypothesis 1). Second, we expect that exercise benefit beliefs mediate the relationship between happiness and exercise behavior, with a stronger indirect effect via psychosocial benefits than physical benefits (Hypothesis 2). Importantly, building on prior studies examining the relationship between various SWB indicators and exercise (e.g., Kushlev et al., 2020), this research defines happiness as SWB, encompassing both life satisfaction and affective well-being (Diener, 1984).

To test the two hypotheses, we aim to conduct three studies with diverse samples from the United States and South Korea (total N = 997), employing multiple methodologies. Study 1 develops a measurement tool to distinguish between psychosocial and physical benefit beliefs, testing Hypothesis 1. Study 2 validates this tool in a separate sample and examines its connection with exercise behaviors, addressing both Hypotheses 1 and 2. Finally, Study 3 replicates the findings by investigating perceived exercise effectiveness and choices within more realistic, scenario-based tasks.

The main objective of Study 1 was to obtain initial evidence to support Hypothesis 1. This hypothesis posited that individuals with higher SWB would hold greater exercise benefit beliefs than those with lower SWB and that the difference in exercise benefit beliefs between happier and less happy individuals would be more prominent in psychosocial than physical benefit beliefs.

Our studies were approved by the Institutional Review Board (IRB) of Seoul National University (IRB No. 2202/001-008).

To analyze our data, we used R (R Core Team, 2020) version 4.2.1 in all studies conducted.

In Study 1, the EFA and CFA results validated our distinction between psychosocial and physical benefit beliefs in the exercise context. Our analysis showed that emotional, cognitive, and social benefits are grouped under psychosocial benefit beliefs, while athletic and rehabilitative benefits fall under physical benefit beliefs, providing initial support for the reliability of the EBB scale. The findings of Study 1 also supported Hypothesis 1, which states that happier individuals hold greater exercise benefit beliefs than the less happy, and this difference is more evident in psychosocial benefit beliefs than physical ones. It is essential to note that our results do not mean happier individuals prioritize psychosocial benefits over physical ones. Rather, while individuals across all levels of happiness generally perceive physical benefits as more significant than psychosocial benefits, this tendency is less pronounced among happier individuals.

In Study 2, we had two empirical objectives. First, we aimed to replicate the findings regarding Hypothesis 1 and to gather initial evidence for Hypothesis 2. We incorporated various exercise behavioral measures, including exercise frequency, intention, and engagement. Second, we sought to validate our EBB scale using another sample from a different cultural background (i.e., the U.S.). Additionally, Study 1 used a single-item measure of life satisfaction, which previous research has validated (e.g., Cheung & Lucas, 2014; Jovanović, 2016; Jovanović & Lazić, 2020). However, we recognize potential reliability concerns with single-item measures and plan to use a full multi-item scale in subsequent studies to enhance reliability.

In Study 2, the CFA results suggest that exercise benefit beliefs were categorized into psychosocial and physical domains, consistent with Study 1, confirming the validity of the EBB scale. Furthermore, Study 2 verified Hypothesis 1, indicating a positive link between happiness and exercise benefit beliefs, with a larger association between SWB and psychosocial than physical benefit beliefs. Study 2 also supported Hypothesis 2, revealing that while psychosocial benefit beliefs mediated the relationship between happiness and exercise behavior, physical benefit beliefs did not. Overall, the findings suggest that happier individuals engage in exercise more because they perceive it as beneficial for psychosocial well-being.

Study 3 aimed to revalidate hypotheses using a more realistic measurement of exercise benefit beliefs, enhancing ecological validity. Participants engaged in scenario-based tasks designed to naturally elicit their beliefs about exercise in response to psychosocial or physical challenges. We hypothesized happier individuals would perceive exercise as more effective, with this perception being stronger for psychosocial than physical challenges (Hypothesis 1). We further expected that these perceptions would mediate the relationship between happiness and the decision to exercise (i.e., exercise choice), with a stronger indirect effect observed via psychosocial challenges (Hypothesis 2).

Study 3 confirmed Hypotheses 1 and 2, suggesting that happier individuals view exercise as a more effective way of dealing with challenges, especially psychosocial ones. This indicates that happier individuals are motivated to exercise even when they need to improve their psychosocial well-being. Additional analysis of various activities revealed intriguing trends, indicating happier individuals generally consider any activity effective in overcoming daily challenges, consistent with previous research on their positive outlook (e.g., Lyubomirsky & Tucker, 1998). However, the stronger association between happiness and psychosocial benefit beliefs than physical benefit beliefs appears to be unique to exercise and not observed in other activities.

Building on the Theory of Planned Behavior (TPB; Ajzen, 1985), Social Cognitive Theory (SCT; Bandura, 1986), and empirical literature (e.g., Lyubomirsky et al., 2005) that identify happiness—subjective well-being (SWB; Diener, 1984)—as an antecedent of exercise behavior, the present study proposed and tested two hypotheses regarding the relationship between happiness and exercise behavior. Hypothesis 1 posited that happier individuals than those less happy would believe more strongly in the benefits of exercise, with this difference being larger for psychosocial benefits (emotional, social, and cognitive) than for physical benefits (athletic and rehabilitative). Hypothesis 2 maintained that these beliefs would mediate the relationship between happiness and exercise, with a more substantial indirect effect in psychosocial than physical benefit beliefs.

We tested these hypotheses through three empirical studies involving 997 participants from the United States and South Korea. All three studies supported Hypothesis 1, while the last two studies provided evidence to champion Hypothesis 2. Specifically, Study 1 developed a novel scale that distinguishes between psychosocial benefits (e.g., “exercise can reduce anxiety”) and physical benefits (e.g., “exercise can increase strength”), suggesting that happiness is more closely related to psychosocial benefits. Study 2 validated this scale, and parallel mediation analyses revealed that psychosocial benefits play a greater role than physical benefits in mediating the relationship between happiness and increased exercise intention, encouragement, and actual exercise frequency. Finally, Study 3 employed a scenario task, and its moderated mediation analysis demonstrated that the link between happiness, exercise benefit beliefs, and exercise choice is moderated by the type of benefit. This further clarifies the underlying mechanism: happier individuals viewed exercise as effective for addressing daily challenges, particularly for psychosocial difficulties rather than physical ones.

Our study contributed to the existing literature in several ways. First, the study developed and validated the Exercise Benefit Beliefs (EBB) scale, which introduces a novel approach to evaluating laypeople’s perceptions of exercise benefits by explicitly differentiating between physical and psychosocial benefits. Building on prior research (Sechrist et al., 1987; Wójcicki, 2009), the EBB scale expands to cover a broader array of psychosocial benefits, including emotional regulation, cognitive development, and prosocial benefits (e.g., Smith & Merwin, 2021), which previous scales did not address. This not only reflects a more comprehensive view of exercise benefits but also supports future research with diverse objectives related to exercise behavior by offering a more nuanced measure of benefit beliefs.

Second, the study examined the cognitive mechanisms underlying the relationship between happiness and exercise, positioning happiness as an antecedent and identifying mediating factors that link happiness to exercise behavior. While existing research highlights their bidirectional relationship (e.g., Steptoe, 2019), prior studies have predominantly focused on how exercise boosts happiness through physical and social functioning (Lera-López et al., 2017; Newman et al., 2014) and physiological pathways (Thorén et al., 1990). Conversely, we focused on the mediating role of exercise benefit beliefs, especially psychosocial ones, in explaining why happiness leads to exercise engagement, suggesting that happier individuals see exercise as fulfilling psychosocial needs. Together, the present work elucidates how some unhappy individuals may overlook these benefits despite exercise’s emotional impact.

Third, the study underscored the significance of the psychosocial benefits of exercise. While the physical benefits of exercise are well-documented, the psychosocial advantages are often overlooked. Ruby et al. (2011) noted that individuals frequently underestimate the intangible benefits of exercise, such as enjoyment of exercise, due to a narrow focus on the unpleasant aspects of starting an exercise routine. However, they also mentioned that this tendency can be addressed and potentially reversed, thereby enhancing the intention to exercise. Furthermore, research indicates that psychosocial benefits have a more substantial impact on exercise intention and behavior compared to physical benefits (e.g., Williamson et al., 2020). Our findings highlighted the importance of promoting beliefs about the psychosocial benefits of exercise to engage in physical activity.

Lastly, the study holds practical implications, particularly for practitioners involved in promoting exercise. A significant proportion of adults (27%) and adolescents (80%) across the globe still do not meet physical activity guidelines set by the World Health Organization (WHO, 2022). Unlike motivation, which often demands sustained and intensive efforts, and traits, social influences, or environmental factors, which are typically resistant to transformation, beliefs represent a uniquely malleable and actionable target for intervention. In other words, brief mindset interventions can effectively shape beliefs, leading to significant changes in exercise behavior. For instance, individuals encouraged to view fitness as a skill that can be developed are more likely to engage in exercise than those who believe it is fixed (Orvidas et al., 2018). Similarly, reframing exercise as an enjoyable activity rather than a rigid obligation significantly increases physical activity (Boles et al., 2021). Likewise, framing exercise as a tool for improving happiness, social engagement, or productivity may be effective in encouraging exercise participation, especially among less happy individuals. Practitioners could highlight psychosocial benefits in gym advertisements and programs, fostering a holistic commitment to regular exercise.

Despite the valuable insights the present study provides, several limitations and future research directions are noteworthy. First, the cross-sectional nature of our design limited our ability to draw definitive conclusions about temporal relationships. While our findings align with the theoretical framework of the TPB, which suggests that background factors such as happiness sequentially shape beliefs, intentions, and behavior, alternative causal pathways remain plausible. For example, exercise behavior may influence beliefs, which then affect happiness. To address this, future research could incorporate longitudinal or experimental designs to establish more precise causal relationships. One promising direction involves mindset interventions (e.g., Boles et al., 2021) that emphasize both the psychosocial and physical benefits of exercise. Comparative analyses examining the impact of such interventions on exercise behavior while accounting for variations in happiness levels would offer valuable insights into the temporal interplay between these factors.

Second, while we accounted for several covariates, including age, gender, ethnicity, and exercise experience, it is crucial to recognize that other demographic and exercise-related variables might also impact our findings. For instance, socioeconomic status (SES) can hinder individuals’ ability to engage in physical activity (e.g., Cerin & Leslie, 2008), potentially attenuating the effects of happiness on exercise benefit beliefs and exercise behaviors. Individuals with lower SES often experience poorer mental health due to diminished health-related behaviors (Wang & Geng, 2019). However, previous studies indicate that the relationship between health behaviors and mental health remains positive and significant, even when controlling for SES factors (e.g., Wickham et al., 2020). This suggests that our findings may be consistent regardless of SES. To deepen our understanding of the relationship between happiness and exercise, future research should investigate the impact of inhibiting mechanisms, including SES, on exercise benefit beliefs.

Third, while we defined happiness by incorporating hedonic aspects of well-being, this focus may limit our exploration of other dimensions, such as psychological well-being (PWB; Ryff et al., 2007) and optimism. Prior literature highlights the role of PWB in enhancing exercise behavior (Edwards et al., 2005) but their bidirectional relationship is underexplored and unclear yet. Future studies should first investigate whether PWB can predict exercise behavior and then how beliefs may mediate this relationship. Additionally, while some may argue that optimism is also associated with healthy behaviors (Kavussanu & McAuley, 1995), Boehm et al. (2018) noted that the evidence supporting this link is relatively weak. In contrast, a robust body of research consistently demonstrates that higher SWB leads to greater physical activity (Diener et al., 2018; Frey & Gullo, 2021; Kushlev et al., 2020; Steptoe, 2019), which is why we focused on SWB in our study. Future research should explore how optimism interacts with belief systems.

Lastly, the study distinguished between physical and psychosocial benefit beliefs. However, some psychosocial benefits may be attributed to genetics and brain functions, blurring the boundaries between physical and psychosocial aspects (Harden, 2023). Despite this concern, we found a significant but slight latent correlation between the two (rs = 0.35 and 0.17 in Studies 1 and 2, respectively). Future studies could explore whether this dichotomy remains in other behaviors that generate physical and psychosocial benefits, such as smoking cessation, diet, and sleep.

Although extensive research shows that happier individuals exercise more, the underlying mechanism remains unclear. This study addresses this gap by examining the role of exercise benefit beliefs in this connection. Our findings suggest that happier individuals perceive exercise as more beneficial to their overall well-being, with the gap based on happiness levels being greater in psychosocial benefits than in physical benefits. Additionally, these beliefs mediate the relationship between happiness and exercise behavior, with a stronger indirect effect for psychosocial benefits. By highlighting the psychosocial benefits of exercise, we can offer practical guidance and support to encourage physical activity, particularly for less happy individuals.