Coronavirus disease 2019 (COVID-19), caused by the SARS-CoV-2 infection, was first identified in China in December 2019 (1). Since the virus started spreading steadily in several countries in all continents, the World Health Organisation (WHO) declared a pandemic in March 2020. Having it posed a serious threat to public health worldwide, many governments introduced lockdowns to reduce the spread of the virus. Since transmission of SARS-CoV-2 is mainly related to direct exposure to aerosolised respiratory particles (2), it was suggested that their spread could be enhanced by high-intensity exercise (3). Indeed, during the different pandemic waves, shutdown of sports activities, centres, and clubs was included among other preventive measures.

However, it is well-known that physical activity (PA) improves physical and psychological well-being at any age. Specifically, PA is beneficial for the preservation of the immune system, cardiorespiratory and muscular fitness, cardiometabolic health, and bone health (4, 5). It is therefore crucial in preventing infections, cardiovascular diseases, type-2 diabetes, and certain types of cancer (6). As for the psychological aspect, PA entails release of endorphins and reduction in the levels of stress hormones such as cortisol and adrenaline, thus being associated with lower levels of stress, anxiety, and depression (7–11).

Given that risk factors for severe COVID-19 include heart and respiratory problems, cancer, diabetes, and obesity (12–15), which might be exacerbated by a sedentary lifestyle and physical inactivity, the WHO reiterated the importance of PA and provided specific guidelines during the pandemic (16). On a psychological level, PA was considered a key strategy to cope with distress associated with the implementation of preventive measures such as lockdowns and quarantines (17, 18). Indeed, physical inactivity can also contribute to mental health conditions that in turn are known to further encourage sedentary behaviours (19), such as depressive symptoms.

Nevertheless, several studies showed that during the COVID-19 pandemic mental health was deeply affected (20, 21), and PA levels substantially decreased while sedentary behaviours increased in several countries (22–24), also in younger age groups (25). Even prior to the COVID-19 pandemic, physical inactivity was recognised as a global health concern (26), with younger individuals also being affected (27). Since this might entail detrimental consequences on the overall well-being of individuals, and risks associated with physical inactivity might as well affect public health in the long term, it is crucial to address this issue across all ages and countries.

Italy was the first country outside of China where SARS-CoV-2 local transmission was detected and that soon implemented some of the strictest anti-COVID-19 measures (28, 29). However, our previous study (30) showed that there is no evidence that shutdown and limitation of sports activities were effective in reducing the spread of COVID-19 in Italy in young Italian athletes, namely children, adolescents, and young adults. Additionally, our findings indicated an increase in Body Mass Index (BMI) within this demographic. In order to deepen these results, we further investigated the impact of the interruption of sports activities on mental health, which is the focus of the present paper. The primary hypothesis asserted that levels of PA performed during the beginning of the second European and North American pandemic wave and the following months are associated with a different mental health status among young Italian non-professional athletes. Secondary aims regard the evaluation of possible differences concerning mental health with respect to sociodemographic variables (such as gender and educational level) and screen time.

Characteristics of the subjects in terms of weekly training sessions are presented in Table 1. Females reported training 1–2 times/week significantly less compared to males (39.0% vs. 60.3%), while demonstrating similar levels of intensive weekly training sessions (>2 times/week). Furthermore, individuals training >2 times/week reported significantly lower screen time (27.5% ≤ 2 h) than those who did not train (18.2%). Similar results were obtained considering periods of openings and closures (Supplementary Table 2).

The current study sought to investigate the relationship between PA and psychological health in various young age groups during the COVID-19 pandemic. Particularly, levels of PA performed during the beginning of the second European and North American pandemic wave and the following months were expected to be associated with a different mental health status among young Italian non-professional athletes. Our findings confirmed this hypothesis, revealing that not engaging in PA was associated with a higher incidence of psychological symptoms in both children/adolescents and youth/young adults. Those who were able to train continuously, both during closures/lockdowns and openings, showed fewer psychological symptoms.

In addition, engaging in outdoor PA or having access to outdoor spaces at home appears to be particularly crucial for children and adolescents. This is in line with previous studies highlighting an association between outdoor activities and psychological well-being (38–42). As suggested by previous research (43, 44), these findings emphasise the need to facilitate outdoor recreation opportunities, which should be taken into account for younger age groups during times of crisis in Italy as well. It should also be considered that outdoor activities reduce the probability of transmission of respiratory viruses (45, 46).

Furthermore, screen time has been found to be associated with psychological symptoms in children and adolescents, as well as youth and young adults. As we discovered, excessive use of electronic devices has a negative impact on psychological well-being (47–50) and is associated with a decrease in PA (51, 52). Over 2 h of daily screen time, in particular, was linked to emotional and peer relationship problems in children/adolescents. Indeed, studies show that increased screen time is linked to lower levels of social competence (53, 54), as well as higher levels of depression and anxiety symptoms (55–57). It is to note that emotional and social competences and PA/sports show a reciprocal relationship, with one positively influencing the other. In fact, PA and sports can enhance emotional and social competences (58, 59), explaining why exercise resulted as linked to the adoption of prosocial behaviour in children/adolescents as well. It is to note that possessing high levels of these competences (such as self-control, empathy, and communication) can in turn improve one's likelihood of engaging in PA and sports activities. Social contact and support from others due to sports activities increases the beneficial effects of physical exercise interventions (60), and these benefits should be taken into account (17). In fact, in a Norwegian cohort study involving 382 children, it was found that there was no clear link between post COVID-19 conditions and the previous infection. Instead, loneliness and lack of PA were shown to be important factors. However, it is important to note that the increase in remote learning has contributed to the amount of screen time.

The current study also discovered significant gender differences. Indeed, male children and adolescents were more prone to present psychological difficulties overall—specifically, conduct problems, hyperactivity/inattention, and lower prosocial behaviour. This is consistent with research showing that males exhibit externalising problems more frequently than females (i.e., dysfunctional acting-out and outward behaviours related to poor impulse control, such as rule-breaking, aggression, and impulsivity) (61–65). However, young adult males presented less psychological symptoms than young adult females. This is in line with previous findings (66) and might be due to the fact that females reported training less than males during the study period.

In a study conducted on 3,245 children and adolescents (67), caregivers reported behavioural changes in 64.3% of children under 6 years old and in 72.5% of those between the ages of 6 and 18 during the COVID-19 pandemic. In both age groups, distress linked to quarantine was significantly associated with such behavioural changes. However, in our study more psychological difficulties were found among children in kindergarten and primary school students, along with middle school students, compared to high school. Indeed, children attending kindergarten, primary and middle schools were more frequently reported as not having trained at all during the study period.

Along with the positive effects of PA on mental health, its beneficial outcomes on physical health, specifically concerning infectious diseases, should be considered as well. By boosting the immune system, PA can help minimise the adverse effects of the infectious process caused by COVID-19 (68). Recent publications showed a reduction in aggravation of the disease, in hospital admissions and a decrease of death from COVID-19 (69, 70). Furthermore, PA can also prevent COVID-19 infection, and the mechanisms can be partially explained by the higher concentration of immune cells, such as T lymphocytes, and the increased resistance of the mucosal immune barrier (salivary IgA immunoglobulin), observed in more physically active individuals (71, 72), providing a greater immunity against different types of viruses and bacteria entering the human body through the oral cavity and upper airways.

Fortunately, COVID-19 showed a very good prognosis in youth (73), and young index cases were found to be significantly less likely than adults to favour viral spread (74). In fact, it has been shown that the increased exposure to various types of viruses during childhood, including some cold coronaviruses, increased the immune response to SARS-CoV-2 (75).

All these factors should be duly considered when determining the appropriate preventive measures to be implemented for the younger demographic, given the impact on the psychological dimensions, which could affect the adoption of health behaviours.

A limitation of this study is that data were collected retroactively by using a self-administered web survey, raising questions about the accuracy of such information. However, the high interpretability of our results and the agreement with previous research suggest that the overall standard was high. Although other unmeasured confounders might affect the outcomes, key athletes' and sport-related characteristics were taken into account, as well as several sociodemographic variables, and a longer questionnaire might have led to lower compliance and accuracy. Lastly, the findings reported in the present paper refer to the young Italian population and may not necessarily apply to other regions and age groups. However, our results are in line with previous studies conducted in other countries investigating the impact of PA on psychological health during the COVID-19 pandemic (43, 76–80).

Ultimately, the present study confirms the positive impact of PA on mental health during the COVID-19 pandemic among younger age groups, and limitation of sports activities as a preventive measure should be considered in light of the associated risks. Indeed, these findings also provide further understanding of the risk-benefit relationship of interrupting sports activities as a preventive measure against contagion, having significant implications for policymakers and healthcare professionals in developing effective strategies to promote PA and mental health in younger populations. Particularly, the psychosocial aspects most related to PA identified in this study can be helpful to identify alternative and targeted solutions for future epidemics/pandemics. Although these results can provide valuable insights on possible solutions, further research is needed to develop effective interventions. The assessment of PA benefits and its promotion is particularly relevant in childhood and adolescents, as it is a critical period for the establishment of future lifestyles and the development of habits that exert a profound impact on overall health throughout the lifespan (81), also affecting public health in the long term.

The current study provides additional evidence supporting the positive impact of PA on mental health among younger age groups during the COVID-19 pandemic. Moreover, it emphasises the importance of considering the potential risks associated with the restriction of sports activities as a preventive measure. Specifically, by assessing the psychosocial dimensions closely linked to PA, targeted strategies can be developed. These findings contribute to a better understanding of the global situation and can be valuable in enhancing the management of infectious diseases in the future.

The raw data supporting the conclusions of this article will be made available by the authors, without undue reservation.

The study was conducted in agreement with the national and international regulations and the Declaration of Helsinki (2000). Approval by the Ethics Committee was not required as the online survey was completely anonymous, and it was not possible to keep track of any identifiable personal data. The studies were conducted in accordance with the local legislation and institutional requirements. Written informed consent for participation in this study was provided by the participants' legal guardians/next of kin. No potentially identifiable images or data are presented in this study.

We want to mention the members of the EuCARE WP4, who supported the development of this study, which is part of the EuCARE Project: Francesca Incardona (1), Chiara Mommo (1), Gibran Horemheb Rubio Quintanares (2, 3, 4), Ana Abecasis (5), Daniela Alves (5), Inês Cruz Alves (5), Marta Pingarilho (5) Pier Luigi Lopalco (6), Susanna Chiocca (7), Ilaria Cutica (8), Davide Mazzoni (8), Nuno Amparo (5), Daniela Carmagnola (9), Claudia Dellavia (9), Gianvincenzo Zuccotti (10, 11), Felix Dewald (2), Rolf Kaiser (2), Nils Bardeck (2), Michael Böhm (2), Michal Rosen-Zvi (12), Yishai Shimoni (12), Sivan Ravid (12), Tal Kozlovski (12), Sofia Seabra (5), Victor Pimentel (5), Mafalda Miranda (5), Giuseppina Tucci (13), Carmen Romero (13), Francesco Vairo (14), Martina Spaziante (14), Valeria Gabellone (6), Giulia Vaglio (6), Fabrizio Fedele (6), Osvaldo Rafael Ramírez Ibarra (15), Victor Martín Escalante Gómez (15), and Mariela González Rodríguez (15).

(1) EuResist Network, Rome, Italy; (2) Institute of Virology, University Clinics of Cologne, Cologne, Germany; (3) Paul Ehrlich Institut, Langen, Germany; (4) Infectious Diseases Department, Instituto Nacional de Ciencias Médicas y Nutrición Salvador Zubitsn, Mexico City, Mexico; (5) Global Health and Tropical Medicine, GHTM, Associate Laboratory in Translation and Innovation Towards Global Health, LA-REAL, Instituto de Higiene e Medicina Tropical, IHMT, Universidade NOVA de Lisboa, UNL, Portugal; (6) Department of Biological and Environmental Sciences and Technology, University of Salento, Lecce, Italy; (7) Department of Experimental Oncology, IEO, European Institute of Oncology IRCCS, Milan, Italy; (8) Department of Oncology and Hemato-Oncology, University of Milan, Milan, Italy; (9) Department of Biomedical, Surgical and Dental Sciences, University of Milan, Milan, Italy; (10) Paediatric Department, Vittore Buzzi Children's Hospital, Milan, Italy; (11) Department of Biomedical and Clinical Science, University of Milan, Milan, Italy; (12) IBM Research, Mount Carmel Haifa, Israel; (13) Organising Bureau of European School Student Unions (OBESSU); (14) National Institute for Infectious Diseases, “Lazzaro Spallanzani” IRCCS, Rome, Italy; (15) Laboratorio Universitario de Diagnóstico Molecular, Universidad de Guanajuato, Mexico.

ET, SR, and OD'E: conception, design, analysis and interpretation of data, and drafting and revising manuscript critically for important intellectual content. GT: conception, design, and drafting and revising manuscript critically for important intellectual content. FB and GC: analysis and interpretation of data and revising manuscript critically for important intellectual content. FG, PG, and SG: conception, design, interpretation of data, and revising manuscript critically for important intellectual content. MI, DR, AS, CS, GP, and NM: conception, design, and revising manuscript critically for important intellectual content. All authors provided final approval of the version to be published and agree to be accountable for all aspects of the work in ensuring that questions related to the accuracy or integrity of any part of the work are appropriately investigated and resolved.