Trends in Physical Activity and Health-Related Fitness

Over the past four decades, patterns of physical activity and health-related fitness have undergone marked shifts across populations. Initially, many countries experienced improvements in certain fitness domains, driven by school‐based programmes and public health campaigns. From the mid-1980s onwards, however, rising sedentary behaviour linked to urbanisation, digital technology and changing lifestyles led to declines in cardiorespiratory endurance among children and adolescents. Muscular strength and speed showed more variable trends, with some populations registering small gains while others plateaued or dipped. Flexibility and coordination have demonstrated mixed trajectories, often declining in parallel with reductions in unstructured play. Socioeconomic factors, sex and age disparities have shaped these trends, revealing widening inequalities in fitness levels. In recent years, some regions have reported stabilisation or modest rebounds in selected components, suggesting that targeted interventions—such as curriculum reforms, community clubs and digital exercise platforms—can arrest or reverse negative secular trends. The global significance of these developments lies not only in the prevention of obesity and cardiovascular risk but also in the promotion of mental well-being and motor skill acquisition. Practical applications range from policy reforms in school physical education to the design of remote or hybrid activity programmes that address barriers to participation and nurture lifelong engagement in physical activity.

Research from Nature Portfolio

Recent studies have charted long-term changes in youth fitness across diverse settings. One large‐scale investigation of rural schoolchildren aged 7–18 revealed that between 1985 and 2000 most fitness components rose, but from 2000 to 2019 cardiorespiratory endurance and muscular power tended to decline, with nuances between sexes and age groups. These findings underscore regional inequalities and the need for age- and gender-specific interventions. A separate cross-sectional analysis of 11–14-year-olds documented that over a 15-year span upper-body strength and coordination increased while cardiorespiratory fitness and flexibility waned in both boys and girls. This pattern highlights the multifaceted nature of health-related fitness and the importance of monitoring distinct fitness domains rather than relying on composite indices alone.

Trends in Physical Activity and Health-Related Fitness publication trend

The graph below shows the total number of articles in trends in physical activity and health-related fitness across all publications each year (not limited to Nature Index journals).

Technical terms

Secular trends: Long-term patterns or directions of change in a population over decades.

Cardiorespiratory fitness: The capacity of the circulatory and respiratory systems to supply oxygen during sustained physical activity, often measured by endurance tests.

Muscular strength: The maximum force a muscle or muscle group can generate in a single effort, typically assessed by tests of isometric or dynamic strength.

Motor performance: The execution of movement tasks that require coordination, balance, speed, and agility, reflecting underlying neuromuscular function.

Health-related fitness: Components of physical fitness—such as endurance, strength, flexibility and body composition—that are linked to health outcomes rather than purely athletic performance.

References

1. Secular trends in physical fitness of rural Chinese children and adolescents aged 7–18 years from 1985 to 2019. Scientific Reports (2023).
2. Secular trends in health-related physical fitness among 11–14-year-old Croatian children and adolescents from 1999 to 2014. Scientific Reports (2021).
3. An Update on Secular Trends in Physical Fitness of Children and Adolescents from 1972 to 2015: A Systematic Review. Sports Medicine (2020).
4. Secular trends in motor performance in Swiss children and adolescents from 1983 to 2018. Frontiers in Public Health (2023).