Physical Activity Intensity Measurement and Association With Adolescent Health: Chartering New Frontiers

Abstract

See Related Article on p.29 See Related Article on p.29 Globally, less than one in five adolescents meet World Health Organization physical activity (PA) guidelines, more than 300 million adolescents have overweight or obesity, and mental and substance use disorders are the leading cause of disability in children and youth [[1]van Sluijs E.M.F. Ekelund U. Crochemore-Silva I. et al.Physical activity behaviours in adolescence: Current evidence and opportunities for intervention.Lancet. 2021; 398: 429-442Abstract Full Text Full Text PDF PubMed Google Scholar,[2]Global action plan on physical activity 2018–2030: More active people for a healthier world. World Health Organization, Geneva2018Google Scholar]. Low PA is associated with increased risk of type 2 diabetes, hypertension, obesity, and poor mental health during adolescence and long-term health risks including heart disease, stroke, diabetes, and several cancers tracking into adulthood [[1]van Sluijs E.M.F. Ekelund U. Crochemore-Silva I. et al.Physical activity behaviours in adolescence: Current evidence and opportunities for intervention.Lancet. 2021; 398: 429-442Abstract Full Text Full Text PDF PubMed Google Scholar,[3]Pascoe M. Bailey A.P. Craike M. et al.Physical activity and exercise in youth mental health promotion: A scoping review.BMJ Open Sport Exerc Med. 2020; 6: e000677Crossref PubMed Scopus (7) Google Scholar]. Youth PA also has implications for establishing later positive PA habits and greater VO2max and metabolic health in adulthood up to age 70 years [[4]Ekblom-Bak E. Ekblom Ö. Andersson G. et al.Physical education and leisure-time physical activity in youth are both important for adulthood activity, physical performance, and health.J Phys Act Health. 2018; 15: 661-670Crossref PubMed Scopus (33) Google Scholar]. Whereas the benefits of PA on adolescent health are well established [[1]van Sluijs E.M.F. Ekelund U. Crochemore-Silva I. et al.Physical activity behaviours in adolescence: Current evidence and opportunities for intervention.Lancet. 2021; 398: 429-442Abstract Full Text Full Text PDF PubMed Google Scholar,[5]Andersen L.B. Harro M. Sardinha L.B. et al.Physical activity and clustered cardiovascular risk in children: A cross-sectional study (the European youth heart study).Lancet. 2006; 368: 299-304Abstract Full Text Full Text PDF PubMed Scopus (1161) Google Scholar], our ability to accurately measure PA intensity categories and distinguish a variety of health impacts of these categories for adolescents continues to evolve as new data processing techniques emerge. Dahlstrand et al. present a compelling analysis of accelerometer-based PA intensities (sedentary, light, moderate, vigorous, and very-vigorous PA) and multiple health outcomes among a cohort of 13-year-old Swedish adolescents drawing from novel methodologies [[6]Dahlstrand J. Fridolfsson J. Arvidsson D. et al.Move for your heart, break a sweat for your mind: Providing precision in adolescent health and physical activity behaviour pattern.J Adolesc Health. 2023; 72: 29-36Google Scholar]. The authors combined data derived from high-resolution categorization of PA intensity categories to improve accuracy of PA measurement in combination with partial least squares regression analysis to address multicollinearity issues with standard regression modeling. This analytic approach enabled the authors to simultaneously address the associations of PA intensity patterns with both cardiovascular (body mass index [BMI] z-score, waist circumference, resting heart rate, diastolic blood pressure, white blood cell count, pulse wave velocity) and mental health indicators (perceived stress and psychosomatic symptoms). Dahlstrand et al. observed that PA intensities at all levels (light–very vigorous) were associated with positive cardiovascular health, particularly BMI z-score, waist circumference, and resting heart rate. However, just moderate and vigorous PA were associated with mental health. Additionally, increased sedentary time was associated with elevated BMI z-score, waist circumference, and markers of cardiovascular health. Their study offers an important contribution to the literature demonstrating that lower intensity PA may promote cardiovascular health in adolescents. This work also further propels our field toward robust PA intensity measurement to improve study quality, accuracy of findings, and recommendations for optimal health. This study also contributes to a growing literature on the importance of positive health promotion among a critical developmental period. Adolescence is characterized by tremendous shifts in health, wellness, and functioning; increased autonomy from parents; and greater participation in risky behaviors [[7]Centers for Disease Control and Prevention National Center for HIVViral Hepatitis, STD, and TB Prevention Division of Adolescent and School Health. Youth risk behavior survey: Data summary and trends report: 2007–2017.https://www.cdc.gov/healthyyouth/data/yrbs/pdf/YRBS_Data-Summary-Trends_Report2023_508.pdfDate accessed: December 13, 2018Google Scholar]. Given increased independence and stronger bonds with peers, adolescents are less likely to adhere to parental advice about health risks and health promoting behaviors. As a result, poor diet, physical inactivity, and other unhealthy lifestyle patterns may be established during this period, contributing to negative health trajectories into adulthood [[8]Sokol R. Ennett S. Gottfredson N. Halpern C. Variability in self-rated health trajectories from adolescence to young adulthood by demographic factors.Prev Med. 2017; 105: 73-76Crossref PubMed Scopus (16) Google Scholar]. In this sense, the teenage years represent a crucial window for interventions that promote positive health behaviors. Replacing sedentary time with light activity has been shown elsewhere to promote positive health and fitness among children and teens [[9]Aggio D. Smith L. Hamer M. Effects of reallocating time in different activity intensities on health and fitness: A cross sectional study.Int J Behav Nutr Phys Act. 2015; 12: 83Crossref PubMed Scopus (0) Google Scholar]. Light intensity PA interventions also may have greater potential to be successful for youth who have difficulties adhering to higher intensity PA interventions or those beginning the intervention with low baseline PA or self-efficacy for PA [[3]Pascoe M. Bailey A.P. Craike M. et al.Physical activity and exercise in youth mental health promotion: A scoping review.BMJ Open Sport Exerc Med. 2020; 6: e000677Crossref PubMed Scopus (7) Google Scholar]. Moreover, light intensity PA programs may be easier to implement successfully in a variety of applied settings, as they require less rigorous training for professionals [[3]Pascoe M. Bailey A.P. Craike M. et al.Physical activity and exercise in youth mental health promotion: A scoping review.BMJ Open Sport Exerc Med. 2020; 6: e000677Crossref PubMed Scopus (7) Google Scholar]. Dahlstrand et al.’s work, by demonstrating that even low intensity PA can offer cardiovascular health benefits, offers additional supporting evidence for successful health behavior change strategies that encourage PA across the intensity spectrum to promote optimal population health. While Dahlstrand et al. should be commended for this novel methodological work, several steps lay ahead to support widespread adoption of these analytic strategies by PA scholars. Further investigation should examine whether total PA volume versus PA bouts at different intensity categories are more effective for health promotion [[10]Tarp J. Child A. White T. et al.Physical activity intensity, bout-duration, and cardiometabolic risk markers in children and adolescents.Int J Obes. 2018; 42: 1639-1650Crossref PubMed Scopus (74) Google Scholar]. We also need to investigate factors that predict PA intensity patterns among youth to identify modifiable intervention targets, such as whether motor competence, which is shown to promote higher intensity PA in adolescence is associated with PA intensities drawing from these novel techniques [[11]Jaeschke L. Steinbrecher A. Boeing H. et al.Factors associated with habitual time spent in different physical activity intensities using multiday accelerometry.Sci Rep. 2020; 10: 774Crossref PubMed Scopus (6) Google Scholar,[12]Lopes L. Silva Mota J.A.P. Moreira C. et al.Longitudinal associations between motor competence and different physical activity intensities: LabMed physical activity study.J Sports Sci. 2019; 37: 285-290Crossref PubMed Scopus (19) Google Scholar]. Additionally, contextual factors such as opportunities for PA and access to PA resources should be considered, as these factors may inform more targeted interventions. Moreover, while evidence suggests that school settings, social and digital environments, and multiutility urban environments may be effective intervention targets, advanced methodologies are required to assess effectiveness for promoting cardiovascular and mental health in these settings [[1]van Sluijs E.M.F. Ekelund U. Crochemore-Silva I. et al.Physical activity behaviours in adolescence: Current evidence and opportunities for intervention.Lancet. 2021; 398: 429-442Abstract Full Text Full Text PDF PubMed Google Scholar]. As noted by the authors, further development of partial least squares regression in PA intensity research is needed, particularly to address potential overestimation of the importance of PA relative to participant characteristics. Notably, data were cross-sectional limiting potential for causal interpretations, mental health data were self-reported, and white blood cell count is a rough indicator of inflammation that could be replaced by proinflammatory markers such as C-reactive protein and interleukin-6. The findings also may lack external validity, due to all participants aged 13 years and having low prevalence of overweight and obesity (11.9% and 2.4%, respectively) in comparison to mean prevalence estimates globally [[1]van Sluijs E.M.F. Ekelund U. Crochemore-Silva I. et al.Physical activity behaviours in adolescence: Current evidence and opportunities for intervention.Lancet. 2021; 398: 429-442Abstract Full Text Full Text PDF PubMed Google Scholar]. Given that PA patterns, hormone levels, and mental health vary greatly across adolescent development, and PA is a strong predictor of both weight status and related cardiovascular and mental health outcomes [[1]van Sluijs E.M.F. Ekelund U. Crochemore-Silva I. et al.Physical activity behaviours in adolescence: Current evidence and opportunities for intervention.Lancet. 2021; 398: 429-442Abstract Full Text Full Text PDF PubMed Google Scholar,[3]Pascoe M. Bailey A.P. Craike M. et al.Physical activity and exercise in youth mental health promotion: A scoping review.BMJ Open Sport Exerc Med. 2020; 6: e000677Crossref PubMed Scopus (7) Google Scholar], repeating this work in other age groups and with longitudinal data to conduct trajectory analyses would strengthen the work. These limitations may also explain differences in findings elsewhere, such as a scoping review on PA and mental health that found positive associations between participation in light and moderate intensity PA interventions and mental health [[3]Pascoe M. Bailey A.P. Craike M. et al.Physical activity and exercise in youth mental health promotion: A scoping review.BMJ Open Sport Exerc Med. 2020; 6: e000677Crossref PubMed Scopus (7) Google Scholar]. In summary, Dahlstrand et al.’s work has potential to shift PA intensity measurement into the next frontier. The authors' findings associating PA intensity categories with both cardiovascular and mental health among adolescents offer the field new directions, replication studies, and particularly longitudinal analyses to pursue. Through the establishment of positive health associations with these methodologies, a next logical step in this research is the design of varied PA intensity interventions in schools and other community-based settings to assess uptake and impact on sustained positive health outcomes for adolescents. Move for Your Heart, Break a Sweat for Your Mind: Providing Precision in Adolescent Health and Physical Activity Behaviour PatternJournal of Adolescent HealthVol. 73Issue 1PreviewAdolescent health benefits of different physical activity (PA) intensities, especially of lower intensities, are debated due to challenges in accelerometer data processing and analyses. Using a new accelerometer data processing method and multivariate pattern analysis, this study investigated the association of PA intensities with indicators of cardiovascular and mental health. Full-Text PDF Open Access