Adolescent Cardiorespiratory Fitness and Future Work Ability.

Importance: Although research indicates that low fitness in youth is associated with a higher risk of chronic disability in men, the association of fitness in adolescence with work ability in working men and women remains unknown. Objective: To examine the associations of adolescent health-related physical fitness with future work ability. Design, Setting, and Participants: This 45-year observational cohort study, conducted in Finland, examined the direct and indirect longitudinal associations of objectively measured health-related fitness in adolescence (in 1976) with self-reported work ability and sickness absence in early middle age (in 2001) and the Work Ability Index in late middle age (in 2021). A countrywide stratified random baseline sample included fitness measurements for cardiorespiratory fitness (CRF) (running 1.5 km for girls and 2 km for boys), musculoskeletal fitness (MF; standing broad jump and sit-ups for both sexes, pull-ups for boys, and flexed-arm hang for girls), and height and weight, from which body mass index (BMI) was calculated. Structural equation modeling-based path analysis, adjusted for age and sex at baseline and for educational level, work-related physical strain, and leisure-time physical activity in late middle age, was conducted. Data analysis was performed from January to July 2023. Main Outcomes and Measures: Self-reported work ability was measured with structured questions in early middle age and with the validated Work Ability Index in late middle age. Results: The final sample from longitudinal analyses (1207 individuals; 579 [48%] male individuals) consisted of participants with fitness measurement from age 12 to 19 years, and work ability assessment from age 37 to 44 years and/or age 57 to 64 years. Higher adolescent CRF was associated with higher work ability (839 participants; ß = 0.12; 95% CI, 0.01 to 0.22; P = .03) and lower sickness absence (834 participants; ß = -0.07; 95% CI, -0.12 to -0.02; P = .004) in early middle age and, indirectly, mediated by work ability in early middle age, with a higher work ability at the end of working age (603 participants; ß = 0.04; 95% CI, 0.001 to 0.08; P = .04). The results remained consistent in both sexes and after adjustment for the confounders. Neither MF nor BMI was associated with work ability (MF, 1192 participants; ß = -0.07; 95% CI, -0.17 to 0.03; BMI, 1207 participants, ß = 0.09; 95% CI, -0.004 to 0.19) or sickness absence (MF, 1185 participants, ß = 0.02; 95% CI, -0.03 to 0.06; BMI, 1202 participants, ß = -0.03; 95% CI, -0.09 to 0.03) in early middle age or with late middle age work ability, mediated by work ability in early middle age (MF, 603 participants, ß = -0.02; 95% CI, -0.06 to 0.01; BMI, 603 participants, ß = 0.03; 95% CI, -0.004 to 0.07). Conclusions and Relevance: These findings suggest that low CRF in youth is associated with poor work ability at the middle and end of working life, which highlights the informative and prognostic value of CRF assessment early in youth. Enhancing CRF in the first decades of life might contribute to better work capacity and productivity in the labor force, which would have implications for health, quality of life, society, and the economy.

The association of adolescent fitness with cardiometabolic diseases in late adulthood: A 45-year longitudinal study.

OBJECTIVES: The aim of this study was to examine the associations of adolescent cardiorespiratory fitness (CRF), muscular fitness (MF), and speed-agility fitness (SA) with middle-aged cardiometabolic disease risk and explore sex differences. METHODS: This 45-year prospective cohort study examined the associations between objectively measured fitness at adolescence (12-19 years) and physician-ascertained diabetes mellitus, elevated blood pressure (BP), and coronary heart disease reported either in early (37-44 years) or late (57-64 years) middle age, and self-measurement of waist circumference (WC) in late middle age. Fitness measurements for healthy adolescents in baseline included CRF (1.5 km [girls] and 2 km [boys] run), MF (standing broad jump, sit-ups, pull-ups [boys], and flexed-arm hang [girls]), and SA (50 m dash and 4 × 10 m shuttle run). Logistic regression and general linear models were adjusted for baseline age, sex, and body mass index (BMI), involving data from baseline and at least one follow-up measurement (N up to 1358, 47% males). RESULTS: Adolescent CRF was inversely, and regardless of adiposity, associated with middle age accumulated burden of cardiometabolic conditions in the whole sample (N = 562, ß = -0.10, 95% confidence intervals [CI] [-0.18, -0.03], p = 0.006), and elevated BP in females (N = 256, OR = 0.71, 95% CI [0.51, 0.91]). Overall, we observed stronger associations in females than in males. An inverse association of adolescent MF and SA with middle-aged WC was observed, but it did not show as consistent associations as with CRF. CONCLUSIONS: In this study, adolescent fitness, particularly CRF, was inversely associated with the burden of cardiometabolic conditions up to 45 years. Promotion of fitness in youth may be beneficial in preventing adulthood cardiometabolic diseases.

Secular trends in 20 m shuttle run test performance of 14- to 15-year-old adolescents from 1995 to 2020.

PURPOSE: To investigate whether Finnish adolescents' cardiorespiratory fitness measured using the 20 m shuttle run test (20mSRT) changed between 1995 and 2020 and to examine between-group variation in the five datasets during the past 25 years. METHODS: Data on five cohorts were collected in 1995 (n = 498), 1998 (n = 796), 2003 (n = 2383), 2010 (n = 1383), and 2020 (n = 719). The 20mSRT was administered, following the exact same protocol, to all cohorts. A general linear contrast model was used to examine cohort differences in the 20mSRT scores. Variation across cohorts was tested using chi-square-based between-group tests. RESULTS: Girls' 20mSRT scores decreased from 1995 to 2010 and remained stable from 2010 to 2020. Boys' 20mSRT scores decreased continuously from 1995 to 2020. In addition, the variation in girls' 20mSRT scores was larger in the 2020 than 2003 cohort, indicating the growth of SRT differences between individuals in 2020 cohort compared to 2003 cohort. Similarly, boys' scores showed greater variation, especially in the 2010 and 2020 cohorts than in the 1998 cohort. CONCLUSION: The results of this study showed an overall decline in the cardiorespiratory fitness performance measured by 20mSRT of Finnish adolescents. Boys' scores decreased continuously from 1995 to 2020, whereas girls' scores remained stable after 2010. Examination of the variation in scores further revealed that the gap in scores between the adolescents with the highest and lowest scores increased over time.

Leisure-time physical activity from adolescence to late middle age and its associations with the COVID-19 pandemic: A 45-year follow-up.

We aimed to investigate the association of self-reported leisure-time physical activity (LTPA) over a 45-years from adolescence to late middle age mediated by LTPA in early middle age. We also explored whether LTPA in adolescence and early middle age was associated with change in LTPA during the COVID-19 pandemic. We constructed a path model employing questionnaire data from three LTPA measurements (1976, 2001, 2021) including duplicated assessment for pre- and during COVID-19 in 2021. The direct and indirect associations between LTPA in adolescence, early middle and late middle age were investigated, as well as the impact of previous LTPA on change in late middle age LTPA due to the pandemic. The number of participants per assessment was: n = 2083; n = 1468 (71% of the original); n = 878 (42%) and n = 867 (42%), respectively. However, the number varied depending on the path examined. LTPA in adolescence was associated with LTPA in late middle age, although the association was not strong. LTPA decreased significantly during the pandemic. Earlier LTPA was associated with change in LTPA between before and during COVID-19 among males. This study is the first to demonstrate an association between adolescent and late middle age LTPA. However, the association across the 45-years was low.

Individual- and environmental-related correlates of moderate-to-vigorous physical activity in 11-, 13-, and 15-year-old Finnish children.

The objective of this study was to analyze the associations of various individual- and environmental-related factors with subgroups of daily, frequent, moderate and low moderate-to-vigorous physical activity (MVPA) among children and adolescents. Data were obtained from the Finnish School-age Physical Activity (FSPA) study 2016 from 4677 national representative 11-, 13-, and 15-year-old children and adolescents. MVPA and individual- and environmental-related factors were assessed by a questionnaire and analyzed by two-level logistic regression. Seventeen of the twenty-one variables were statistically significantly associated with MVPA. However, only three variables were statistically significant in all MVPA subgroups, whereby self-directed PA at least twice a week, fewer perceived barriers, and higher peer support increased the odds of participating in more MVPA. The results from this study showed essential differences among the MVPA subgroups, also supporting previous findings, whereby various individual- and environmental-based factors are associated with children and adolescents' levels of MVPA. Challenges to designing and implementing effective interventions are based on the need to account for individual differences within the population, as well as the varied connections between PA with different social and physical environments where children and adolescents' PA takes place. PA interventions with various actions at multiple levels are warranted.

Cardiorespiratory performance and physical activity in normal weight and overweight Finnish adolescents from 2003 to 2010.

We investigated changes in cardiorespiratory performance, BMI and leisure-time physical activity among Finnish adolescents from 2003 to 2010. In addition, we compared cardiorespiratory performance levels between normal weight and overweight adolescents, grouped according to their physical activity. Participants were a national representative samples of 15-16-year-old adolescents in their final (ninth) year of comprehensive school in 2003 (n = 2258) and in 2010 (n = 1301). They performed an endurance shuttle run test and reported their height and weight and leisure time physical activity on a questionnaire. Results showed no significant secular changes in cardiorespiratory performance from 2003 to 2010. The mean BMI increased in boys. Leisure-time physical activity increased among normal weight girls. Adolescents of normal weight had better cardiorespiratory performance than those classified as overweight at both assessment points. BMI-adjusted physical activity was a significant determinant for cardiorespiratory performance among overweight adolescents, and very active overweight adolescents had similar cardiorespiratory performance levels as moderately active adolescents of normal weight. The results of the present study support the idea that the physical activity has the great importance for the cardiorespiratory performance in adolescents. Overweight adolescents, in particular, benefit from higher levels of physical activity.

Adolescent physical fitness and activity as predictors of adulthood activity.

A 25-year population-based study was conducted to determine how physical fitness and participation in leisure-time physical activity in adolescence (age 12-18 years) predict leisure-time physical activity in adulthood (age 37-43 years). In 1976, five field tests were conducted to measure muscular fitness, agility and aerobic capacity, and self-report weekly frequencies of activity were obtained by questionnaire. A modified questionnaire was repeated in 2001, when participants were age 37-43 years (N = 1525). On the basis of the questionnaire, a physical activity index was calculated both in 1976 and 2001. The odds ratios (OR) for being inactive in adulthood among those who were physically very active in adolescence compared with those who were inactive in adolescence was 0.13 for males (95%CI: 0.06-0.31) and 0.28 for females (95%CI: 0.13-0.59). The odds ratio for adult inactivity among males in the highest versus lowest fitness group in adolescence was 0.24 (95%CI: 0.07-0.81). Activity in adolescence predicted activity in adulthood in both males and females. The risk for adult inactivity was significantly lower for those who were physically active in adolescence. In addition, high fitness predicted adult activity among males but not among females.

Secular trends in muscular fitness among Finnish adolescents.

AIM: To investigate secular change over time in health-related muscular fitness and how leisure time physical activity (LTPA), sport club participation, and body mass index are associated with muscular fitness in adolescents. METHODS: Two cross-sectional samples of Finnish 13-16-year-old adolescents were studied in 1976 (n = 643; 312 boys and 331 girls) and in 2001 (n = 579; 308 boys and 271 girls). Muscular fitness index was calculated as the sum of age- and sex-specific z-scores of four tests measuring muscular fitness and agility. Height and weight were also measured. Self-reported weekly frequency of LTPA of at least 30-min duration and regularity of participation in organised sport were obtained by questionnaire. Identical methods were used in 1976 and 2001. RESULTS: Muscular fitness index was higher in 2001 than in 1976 in both boys (by 0.77 points, p = 0.008, effect size d = 0.17, small difference) and girls (1.01 points, p = 0.004, d = 0.20, small difference). Sport club participation, body mass index, and participation in LTPA together explained more of the muscular fitness index variance in 2001 than in 1976 in both boys (coefficient of determination from 0.10 to 0.24) and girls (from 0.25 to 0.40). CONCLUSIONS: The muscular fitness of 13-16-year old adolescents slightly improved over time. Organised LTPA showed a stronger association with muscular fitness in 2001 than in 1976. Due to increased polarisation in fitness, in health promotion more attention should be paid on adolescents' health-related fitness and its association to LTPA.