Introduction
Adolescence is a period of significant physical and
emotional changes, during which young people undergo
experiences that may shape their development and have a
substantial impact on their mental well-being and overall
health. Globally, the World Health Organization (WHO)
estimates that 14% of adolescents aged 10 to 19 experience
a mental disorder, with anxiety being the most common
among those aged 15 to 19.1 Suicide is also one of the
leading causes of death during adolescence, highlighting
how critical this stage is for mental health, as adolescents
often engage in risky behaviors that may harm their
emotional well-being.
In Portugal, the 2015 National School Health Program
identified mental health as a priority area for intervention,
aiming to strengthen students’ socio-emotional skills by
promoting protective factors for lifelong health.2
According to the WHO, physical activity provides
important mental health benefits, helping to prevent
cognitive decline, depression, and anxiety.3 However,
physical inactivity remains highly prevalent among
Portuguese adolescents: WHO data indicate that 78% of
boys and 91% of girls do not meet the recommended levels
of physical activity.4 Physical activity plays a key role in
maintaining well-being and promoting healthy behaviors,
making it essential to foster regular participation in physical
activity during adolescence.
The COVID-19 pandemic further emphasized the
importance of encouraging physical activity, as this
behavior is now recognized as a key determinant of both
physical and mental health.5 Pender et al. state that regular
physical activity among adolescents helps reduce depressive
symptoms and cognitive decline while enhancing overall
well-being.6 Physical activity serves as a protective factor
for mental health, whereas physical inactivity may
contribute to the development of mental health problems.7
Multiple factors can negatively influence adolescents’
attitudes toward physical activity. One primary concern is
technology dependence, particularly the excessive use of
social media, video games, and television, which directly
affects adolescents’ quality of life. Adolescents who spend
more than two hours per day in front of screens tend to
report poorer mental health outcomes.8 A study by
Chortatos et al.9 found that those who spent less time on
multimedia activities (such as TV/movie streaming or
gaming) were significantly more likely to participate in
physical activity during the week or on weekends. These
findings highlight the harmful effects of excessive screen
time on adolescents’ daily lives and reinforce the need for
interventions that promote healthy lifestyle habits.
Family influence is also a key factor in shaping adolescents’
physical activity behaviors. In a study by Kefeliçol and
Altay,10 adolescents whose parents had higher educational
attainment and strong family relationships were more likely
to engage in healthy behaviors. The study also found that
adolescents who did not live in nuclear families reported
fewer healthy habits compared to those who did. These
results are supported by Sollerhed et al.,11 who noted that
adolescents with good subjective health, higher levels of
physical activity, and greater satisfaction with school tended
to come from families with stable financial conditions. In
contrast, adolescents whose parents had lower levels of
education were more likely to spend excessive time in front
of screens.9
Sedentary behavior among adolescents has become an
increasingly pressing public health concern, with significant
physical and mental health consequences. It is well
established that sedentary lifestyles are a risk factor for
anxiety, depression, cardiovascular disease, and type 2
diabetes, and are also associated with depressive symptoms,
suicide attempts, and premature death in adolescents and
young adults.12,13 Pontes et al. also point out that physical
inactivity is more prevalent among girls than among boys.13
In addition to its well-established contribution to the
healthy growth and development of children and
adolescents, regular physical activity fosters the
development of social skills and provides numerous
psychological, emotional, and cognitive benefits, with
positive effects on academic performance.12 Additionally,
Portuguese children and adolescents spend an average of
545 minutes per day engaged in sedentary activities.12
Regular physical activity contributes to the improvement of
positive health and lifelong well-being. As such, the school
years represent a unique opportunity to intervene and
prevent sedentary habits, since many unhealthy behaviors
are established in this period.12
Schools play a fundamental role in shaping adolescents, not
only in the academic domain but also in promoting health
and encouraging the adoption of healthy habits.
Nurses are the health professionals best positioned to lead
health promotion initiatives in school settings.6 Their close
relationship with the community is essential to the health
planning process, as it allows them to identify the
population’s actual needs and develop appropriate
strategies that equip individuals to adopt healthier lifestyles.
According to the principles set forth in the Ottawa
Charter,14 it is the responsibility of health professionals to
empower the population through health promotion,
enabling individuals to achieve their full health potential by
taking control of the factors that determine it.
This project is grounded in the European initiative
Promoting Mental Wellbeing through Online Exchange in Secondary
Schools (wExchange), co-funded by the European Union.
It was developed through a consortium of higher education
institutions and secondary schools in Finland, Slovenia,
Greece, and Portugal to promote adolescent mental well-
being through peer education. The present project aimed
to equip 8th-grade students with the knowledge and skills
to adopt healthy physical activity habits that support mental
well-being. Peer education was the core strategy employed
during the community intervention phase.
Methods
A cross-sectional observational study was conducted, based
on the Health Planning methodology proposed by