The relationship between anxiety and physical activity has been the subject of extensive research, with numerous studies highlighting the interplay between these two factors (1–6). To this end, the current evidence has consistently demonstrated the beneficial effects of physical activity on reducing symptoms of anxiety and improving mental well-being in various populations (7–10). A meta-analysis by Rebar et al. (11) emphasized the antidepressive and anxiolytic effects of physical activity, particularly in non-clinical adult populations.

The impact of physical activity on anxiety has also been studied in specific populations, such as students, demonstrating a negative relationship between physical activity and anxiety among secondary school students, indicating the potential benefits of a physically active lifestyle for the students' mental health (12). From a psychological perspective, Kayani et al. (13) suggested that the relationship between physical activity and academic anxiety is mediated by psychosocial factors, highlighting the complex interplay between these variables. Even with this complexity in mind, the prevalence of physical inactivity and anxiety among students still has significant implications for public health, mental well-being, and academic performance (13–15), and it has aroused interest in this field of research. As an example of this, Tabor et al. (16) investigated the negative relationship between smartphone usage and physical inactivity, emphasizing the importance of physical activity in managing anxiety (17). Moreover, Chao et al. (65) found that higher levels of physical activity were associated with lower risks of experiencing anxiety symptoms among Chinese college students, highlighting the global relevance of this relationship. Additionally, Wiet et al. (18) inferred from their study that physical activity is more effective than no treatment and as effective as traditional forms of treatment, including cognitive therapy and antidepressant medication, in addressing anxiety (19, 20).

In support and affirming of the evidence, the Association of Southeast Asian Nations (ASEAN) region has highlighted that the prevalence of anxiety among students has been linked to lifestyle factors, including physical inactivity and sedentary behavior (21). This link to lifestyle factors underscores the need to address not only the psychological aspects but also the lifestyle correlates of anxiety among students. The prevalence of physical inactivity and anxiety among students has been studied in various contexts, including during the COVID-19 pandemic, where the incidence of anxiety has been found to exceed that of the general population significantly (22, 23). These findings emphasize the need to understand the interplay between environmental, societal, and individual factors contributing to physical inactivity and anxiety among students. The research gap in the existing literature is evident in the limited attention given to physically inactive students from countries across all continents regarding their anxiety rates. While numerous studies have explored the relationship between physical activity and anxiety among students in specific regions or cultural contexts (24), there is a lack of comprehensive research focusing specifically on physically inactive students on a global scale. The existing body of research tends to focus on active populations or localized settings, leaving a crucial need for broader, more inclusive studies that address the unique experiences and challenges faced by inactive students worldwide (1, 2, 14, 16). This gap underscores the importance of understanding how inactivity influences mental health across diverse cultural, social, and geographical landscapes.

Identifying countries with higher rates of physical inactivity and anxiety among students is crucial for targeting vulnerable populations and developing effective interventions to promote physical activity and prevent anxiety-related issues (25). By focusing on these high-risk groups, we can develop more tailored approaches to safeguard students' mental health and foster academic success. In this context, employing methods that yield precise, actionable insights is particularly valuable, as they enable the creation of time-efficient interventions that can mitigate anxiety and support well-being. This study, therefore, implements a hierarchical clustering method to categorize countries based on students' pre-exam anxiety levels, specifically distinguishing between two subgroups: physically active and inactive high school students.

The HC algorithm identified two major clusters with subdivisions: first, five clusters [two clusters with high (H-1 and H-2) and three clusters with low anxiety rates (L-1, L-2, and L-3) for the low physically active students], and second, four clusters [two clusters with high (H-1 and H-2) and three clusters with low anxiety rates (L-1, L-2, and L-3) for the low physically active students]. The results of the analysis acknowledging low and highly physically active students and the algorithm performance after being tested by the evaluation metrics are described step-by-step below.

The present study sought to identify patterns of pre-exam anxiety among high school students, distinguishing between those who engage in moderate or vigorous physical activity and those who are physically inactive. The results showed that countries with a higher incidence of physically inactive students generally exhibited higher levels of pre-exam anxiety compared with their physically active counterparts. This finding reinforces the extensive literature associating regular physical activity with psychological benefits, including the reduction of anxiety and stress symptoms.

Initially, in recent years, the practice of physical activity has been widely studied as a protective factor for mental health, particularly concerning anxiety (33, 34). Studies indicate that regular physical exercise can act as a modulator of the central nervous system, reducing cortisol levels, a hormone associated with stress (35–37), and increasing the release of neurotransmitters such as endorphins and serotonin, which promote feelings of well-being (38, 39). Initially, in recent years, the practice of physical activity has been widely studied as a protective factor for mental health, particularly anxiety (33, 34). Studies suggest that regular physical exercise can act as a modulator of the central nervous system, reducing cortisol levels, a hormone associated with stress (12, 36), and increasing the release of neurotransmitters such as endorphins and serotonin, which promote feelings of well-being (38, 40). These mechanisms partially explain why physically active students exhibit lower levels of anxiety, as evidenced by the results of the present study. However, it is important to note that, despite a general trend of lower anxiety levels among physically active individuals, this relationship was not universally observed across all samples. This suggests that, while physical activity is beneficial, other factors, such as the intensity of academic stress and expectations surrounding academic performance, may influence anxiety levels (41). Therefore, in such cases, exercise alone may not be sufficient to fully mitigate the impact of academic pressure on students' mental health. Emerging neuroimaging studies provide further insight into the relationship between physical activity and anxiety. Exercise has been shown to influence amygdala reactivity and prefrontal cortex function, enhancing emotional regulation and resilience.

Furthermore, it is plausible that the beneficial impact of physical activity on reducing anxiety is influenced by variables such as the type, frequency, and intensity of the exercise performed (42, 43). Generally, engaging in physical exercise, regardless of its intensity—moderate or high—is widely recognized as a contributing factor to decreased anxiety (44, 45). However, in highly competitive contexts, physical activity can, paradoxically, exacerbate anxiety levels (18, 46–48). In this sense, exercises conducted in non-competitive environments tend to be more effective in mitigating anxiety levels, while activities in competitive situations can intensify stress, especially in individuals who are already under high pressure (48, 49). The consistently low anxiety levels reported by Czech students, regardless of physical activity status, suggest that cultural and educational factors may play a protective role. The Czech education system is characterized by reduced high-stakes testing pressure compared with other countries, which may lower exam-related stress (50). Additionally, cultural attitudes toward well-being and academic resilience may buffer anxiety (51). In countries such as Brazil or Malaysia, the intensity of entrance examinations and competitive academic environments may exacerbate anxiety (23). In contrast, Scandinavian or Central European education systems often emphasize holistic development over performance metrics, potentially explaining the lower anxiety levels reported (52). In countries such as Costa Rica or the Dominican Republic, scalable community-based physical activity programs could be integrated into school curricula, emphasizing inclusive participation over performance (53, 54). Mental health literacy campaigns adapted to cultural norms could also help destigmatize anxiety and promote help-seeking behaviors (55). Thus, the variability observed in anxiety levels among physically active students may be associated not only with the types of exercise but also with the context in which they are performed, as well as the level of stress to which students are exposed.

Physically active students in countries such as Russia and the United Arab Emirates (UAE) often experience high anxiety due to academic and cultural pressures, despite the mental health benefits of exercise. Studies show elevated anxiety among UAE students, especially females during the COVID-19 pandemic (56), and among Russian medical students facing intense academic demands (57), where in these contexts, physical activity might be associated with performance pressure (e.g., competitive sports). While physical activity generally supports mental health, it may not offset anxiety when institutional stress and mental health stigma are present (39, 58–60). Regarding physically inactive students, the higher levels of anxiety observed in the study reinforce the literature highlighting the mental health risks of a sedentary lifestyle, especially among adolescents. Various studies demonstrate that sedentary behavior is associated with compromised mental health (61–64). Additionally, the lack of physical activity can significantly contribute to the worsening of anxiety, as sedentary individuals often have greater difficulty coping with stress and pressure situations (64). The absence of exercise can negatively affect emotional well-being, reducing the ability to face daily challenges, such as those related to the academic environment, which ultimately intensifies anxiety, especially during peak demand periods such as exams (61, 62).

Despite its promising findings, this study has some limitations that should be considered. First, the generalizability of the results may be restricted by the data source used, as the sample is limited to students who participated in the PISA study, which may not adequately represent all high school students in a global context. Moreover, the dataset considered the average of the percentual values of anxiety for each country, which could lose an essential variability component within each country, that could improve the clustering breakdown. Additionally, the study's focus on 15-year-old students may not encompass the full diversity of age groups and educational environments among high school students. It is also important to note that self-reported data may have introduced response biases, as the participants themselves assessed the levels of physical activity and anxiety. These biases may inflate the correlation between the two variables. The sample was selected based on its scope and standardization; PISA 2018 includes a broad spectrum of countries with consistent measures across multiple domains. However, this selection may not fully capture nuances in less-represented regions or local socioeconomic disparities, potentially limiting the generalizability of findings to underrepresent cultural or educational systems.

Although the study revealed significant associations between physical activity and anxiety levels, it is crucial to recognize that reducing anxiety through exercise should be understood as part of a broader approach to promoting mental health. Interventions that focus exclusively on physical activity may not be sufficient to effectively address the complexity of factors influencing pre-exam anxiety, especially in contexts where academic stress is high and emotional support is limited. Therefore, it is essential that physical activity is integrated with other forms of psychosocial support, such as counseling and stress management, in order to enhance the beneficial effects on students' mental health. The outputs of this study can be used by policymakers from the most affected countries by the issues and consequences of anxiety to the scholarly students' mental health in building educational projects and meetings with parents and teachers, which helps the scholarly community to be more conscious and empowered to prevent long-term anxiety levels and ensure good academic development for the most vulnerable students. While general recommendations are important, we recognize the need for context-specific strategies. For example, in Brazil—one of the countries with the highest anxiety levels—policymakers could consider mandatory inclusion of physical education (PE) at all high school levels, integrated with mindfulness and stress management curricula. Collaboration between schools and mental health professionals may also help develop anxiety screening protocols and physical activity interventions tailored to students' needs. For future research, similar clustering methods can be implemented in case studies in different realities, thus providing the opportunity to make rich insights when comparing the findings across the diversity of socioeconomic and demographic factors among students. The employment of similar models in other age groups, such as university students, can also add to the particularities of anxiety in different academic periods of a person’s life. Finally, longitudinal approaches incorporating time series analysis plus clustering can be very explanative of long-term changes in anxiety levels among students. Future studies should also consider incorporating objective measures (e.g., accelerometers and validated clinical anxiety inventories) to validate these findings.

We conclude that the hierarchical clustering presented good performance in highlighting the most anxious countries in pre-exam, adjusting the clustering by physical activity groups. The countries with respective low physically active students were clustered within five clusters, in which Brazil (82%) and the Dominican Republic (81%) had the most anxious pre-exam students and the Czech Republic (35%) had less anxious students at the pre-exam moment. Regarding the physically active students, these countries were grouped within four clusters, where Malaysia (82%), Brazil (81%), and Costa Rica (81%) were the most anxious countries and the Czech Republic (35%) had the lower rates of anxiety among the physically active students.