Sleep duration and cardiorespiratory fitness in adolescents: Longitudinal analysis from the LabMed study.

PURPOSE: We aimed to investigate longitudinal associations between sleep duration and cardiorespiratory fitness, in adolescents. METHODS: Sleep duration was self-reported and cardiorespiratory fitness was assessed by the 20 m shuttle run test, both at baseline and follow-up (2-year follow-up). Participants were 734 Northern Portuguese adolescents (349 girls), aged 14.6 ± 1.8 years, from the LabMed study. RESULTS: Significant decreases were found between baseline and follow-up for sleep duration, whereas for cardiorespiratory fitness there was an increase. Adolescents with short sleep duration at baseline had lower cardiorespiratory fitness at follow-up, comparing to those meeting the sleep guidelines (odds ratio [OR] = 0.506, 95% confidence interval [CI]: 0.326-0.785; p = .002 for whole week; OR = 0.597, 95% CI: 0.407-0.875; p = .008 for weekdays). Girls who were short sleepers at baseline had lower odds of having a healthy cardiorespiratory fitness at follow-up, comparing to those meeting the sleep guidelines (OR = 0.311, 95% CI: 0.158-0.613; p < .001 for whole week; OR = 0.469, 95% CI: 0.262-0.838; p = .011 for weekdays). No significant associations between sleep duration and cardiorespiratory fitness were found for boys. DISCUSSION: There was a significant longitudinal association between short sleep duration and lower cardiorespiratory fitness levels, particularly in girls. Future interventions targeting adolescents' sleep duration should acknowledge behavioral differences between genders, as well as different behaviors adopted by boys ang girls, specifically on weekends.

Cardiovascular health behavior and blood pressure in adolescents: A longitudinal analysis.

BACKGROUND: The ideal cardiovascular health behaviors (ICHB) have been associated with a subsequent positive health status in adults. However, evidence regarding blood pressure (BP) and ICHB in adolescents is scarce. The aim of this prospective cohort was to evaluate the impact of accumulation of ICHB on BP values in adolescents over two years. METHODS: This is a longitudinal analysis with 445 adolescents (232 girls) aged 12-18 years old. Resting blood pressure was measured at baseline and 2 years later, and ICHBs at baseline according to standard procedures. Based on the American Heart Association definition, the ICHB index was defined as a sum of meeting the ICHBs (from 0 to 4, where 4 would be the healthiest profile of all ICHBs) for a healthy diet, physical activity, smoking status and body mass index. RESULTS: Adjusted means values (ANCOVA) of BP parameters through achievement of a greater number of (between 1-4) the ICHBs (adjusting for potential confounders, age, sex, pubertal stage and socioeconomic status) showed that, as increase the number of ICHB accumulated as a lower the BP levels [ICHB and SBP (F3.435) = 4.501, p = 0.004), DBP (F(3.435) = 2.725, p = 0.044), pulse pressure (F(3.435) = 4.004, p = 0.008), and rate pressure product (F(3.435) = 2.866, p = 0.036)] over two years. CONCLUSION: A lower number of ICHB (smoking status, body mass index, physical activity, and diet) during adolescence play a key role on blood pressure over two years. A higher number of ICHB is seen to be associated with a lower risk of short-term, hypertension.

Cardiovascular health behavior and cardiorespiratory fitness in adolescents: a longitudinal study.

Cardiorespiratory fitness has been substantially associated with health status. However, longitudinal studies on cardiorespiratory fitness and ideal cardiovascular health behavior (ICHB) in adolescents are scarce. The aim of this study was to evaluate the longitudinal association between ICHB (at baseline) and cardiorespiratory fitness (at follow-up). This is a 2-year prospective analysis of 445 adolescents (232 girls) aged 12-18 years. The ICHB was developed by the American Heart Association as meeting the ideal health behaviors for a healthy diet, physical activity, smoking status, and body mass index. ANCOVAS adjusted by age, sex, pubertal stage, socioeconomic status, and cardiorespiratory fitness showed that the higher the number of ICHB metrics accumulated at baseline (from 1 to 4), the higher the cardiorespiratory fitness levels over a 2-year period (p = 0.038). In logistic regressions, after adjusting for potential confounders, the odds ratios for having high cardiorespiratory fitness at follow-up was 4.9 (95% CI, 1.2-20.1, p = 0.02) for those who accumulated all four metrics of ICHB, when compared to those with 1 or less metrics of ICHB. In addition, the higher the number of ICHB metrics accumulated, the higher the likelihood of having a high cardiorespiratory fitness level over a 2-year period (p for trend = 0.01). CONCLUSION:  We identified a significant association between ICBH and cardiorespiratory fitness in adolescents. Therefore, improving ICBH in adolescence is likely to benefit the cardiorespiratory fitness. WHAT IS KNOWN: • Smoking status, body mass index, physical activity, and diet are associated to cardiorespiratory fitness in adulthood. • Lifestyle behaviors such as physical activity, smoking, body weight, and healthy diet are individually linked with cardiorespiratory fitness and, however, have not been examined jointly, as combined health behaviors. WHAT IS NEW: • Accumulation of cardiovascular health behavior metrics was positively associated with cardiorespiratory fitness at a 2-year follow-up, in adolescents. • Meeting all the four metrics of ideal cardiovascular health behavior seems important for healthy cardiorespiratory fitness during adolescence.

The relationship between height and fruit/vegetable intakes in adults: A nationwide cross-sectional study.

Background: Worldwide, fruit and vegetable intake is below recommendations. There is increasing evidence to suggest an association between height and diet. Aim: to analyse the associations of fruit and vegetable intake with attained height in Portuguese adults. Methods: A representative sample of 17 480 Portuguese adults (56.7% women) participated in this cross-sectional study. The survey comprised sociodemographic characteristics and self-reported height and weight. We performed regression models to assess the associations between height and fruit and vegetable consumption. Results: Compared with no intakes, those men with higher fruit and vegetables intake had 0.54 cm (95% CI 0.04; 1.04) greater height. Also, women with higher intakes of vegetables, fruit and vegetables combined were directly associated with a greater height of 0.29 cm (95% CI 0.03; 0.56 in vegetables) and 0.51 cm (95% CI 0.09; 0.93 in fruit and vegetables combined). Conclusion: Greater consumption of fruit and vegetables was directly associated with higher height in adults. From a health promotion perspective, intervention programmes aiming at improving fruit and vegetable intake should be highlighted so that full height potential is achieved.

The mediating role of adiposity in the longitudinal association between cardiorespiratory fitness and blood pressure in adolescents: LabMed cohort study.

BACKGROUND: The aim of this prospective cohort study was to examine whether the association between the cardiorespiratory fitness (CRF) at baseline and blood pressure (BP) at follow-up is mediated by adiposity in adolescents. MATERIALS AND METHODS: The sample comprised 734 adolescents (349 girls) aged 12-18 years from the LabMed Physical Activity Cohort Study. The variables of interest were measured in 2011 (baseline) and in 2013 (2-year follow-up). CRF was assessed by the 20-m shuttle run test. Body mass index, waist circumference, body fat percentage, pubertal status and resting BP were assessed according to standard procedures. Boot-strapped mediation procedures were performed, and indirect effects (IE) with confidence intervals (CI) not including zero were considered statistically significant. RESULTS: After adjusting for potential confounders, body mass index acted as a mediator of the relationship between CRF and systolic BP (IE = -0. 023; CI = -0.039; -0.009), pulse pressure (IE = -0.023; CI = -0.034; -0.012) and rate product pressure (IE = -2.839; CI = -5.329; -0.340). Similar results were obtained for waist circumference as mediator for systolic BP (IE = -0.019; CI = -0.033; -0.005), pulse pressure (IE = -0.017; CI = -0.028; -0.007) and rate product pressure (IE = -3.793; CI = -6.097; -1.689). Likewise, body fat percentage mediated the association for: systolic BP (IE = -0.029; CI = -0.048; -0.010), pulse pressure (IE = -0.027; CI = -0.041; -0.013) and rate product pressure (IE = -4.280; CI = -7.488; -1.264). CONCLUSIONS: Adiposity mediated the association between CRF and BP in adolescents. Therefore, both optimal CRF and adiposity levels are important to maintain normal BP ranges throughout adolescence.

Physical fitness attenuates the genetic predisposition to obesity in children and adolescents.

Obesity is an important risk factor associated with non-communicable cardiometabolic diseases. Previous studies have indicated that children and adolescents with a predisposed genetic risk for obesity could benefit from an active lifestyle, but there are no studies investigating whether physical fitness moderates the association of genetics and obesity. The aim of this study was to verify the moderating role of physical fitness in the relationship between genetic risk score (GRS) and body mass index (BMI) in children and adolescents. This cross-sectional study was carried out with 1471 children and adolescents, aged between 6 and 17 years from Santa Cruz do Sul, Brazil. Weight and height were assessed to determine BMI. Physical fitness components (cardiorespiratory fitness [CRF], lower limb strength [LLS], upper limb strength, and abdominal strength) were evaluated. The GRS was based on previously associated obesity single-nucleotide polymorphism rs9939609 (FTO), rs6548238 (TMEM18), and rs16835198 (FNDC5). Moderation analyses were tested using linear regression models, and the interactions were represented by physical fitness components X GRS (categorical variable). All analyses were adjusted for skin color/ethnicity, sex, and sexual maturation. Significant interactions for CRF (P = 0.041), LLS (P = 0.041), and abdominal strength (P = 0.046) X 5 and 6 risk alleles with BMI were found only in adolescents. In addition, there was evidence that fitness components attenuated the high genetic predisposition to high BMI. Physical fitness components are moderators in the relationship between GRS and BMI in adolescents. These findings highlight the need for interventions targeting to improve this aspect, which is an important health indicator in all ages.

Neck circumference and cardiometabolic risk in children and adolescents: the moderator role of cardiorespiratory fitness.

BACKGROUND: The increased incidence of cardiometabolic risk factors has become a public health issue, especially in childhood and adolescence. Thus, early identification is essential to avoid or reduce future complications in adulthood. In this sense, the present study aimed to verify the influence of cardiorespiratory fitness (CRF) as a moderator in the association between neck circumference (NC) and cardiometabolic risk in children and adolescents. METHODS: Cross-sectional study that included 2418 randomly selected children and adolescents (52.5% girls), aged 6 to 17 years old. Anthropometric measurements, such as NC and body mass index (BMI), and CRF was measured by the six-minute running/walking test, as well as cardiometabolic risk (systolic blood pressure, glucose, HDL-C, and triglycerides), were assessed. RESULTS: For all age groups, NC showed a negative relationship with CRF. A significant interaction term was found for CRF x NC with cardiometabolic risk for children (6 to 9 years old), early adolescents (10 to 12 years old), and middle adolescents (13 to 17 years old). It was found that children who accomplished more than 1092.49 m in CRF test were protected against cardiometabolic risk when considering NC. In adolescents, protection against cardiometabolic risk was found when the CRF test was completed above 1424.14 m and 1471.87 m (early and middle stage, respectively). CONCLUSIONS: CRF is inversely associated with NC and acts as a moderator in the relationship between NC and cardiometabolic risk in children and adolescents. Therefore, this detrimental health impact linked to fatness might be attenuated by improving CRF levels.

Association of Adipocytokines and Inflammatory Biomarkers with Blood Pressure in Adolescents: A Longitudinal Analysis.

BACKGROUND AND AIMS: Several cross-sectional, but few prospective, studies suggest that inflammation may be involved in the development of high blood pressure. We examined markers of inflammation for their associations with blood pressure levels over a two-year period in healthy adolescents. METHODS AND RESULTS: The sample comprised 406 adolescents (209 girls) aged 12-18 years in the LabMed Physical Activity Study were followed-up for 2 years. Anthropometric (weigh, height, BMI), markers of inflammation (high sensitivity C-reactive protein, complement factors C3 and C4, fibrinogen, leptin and adiponectin) and ambulatory blood pressure (BP) were collected. Socioeconomic status, pubertal development, adherence to Mediterranean diet and cardiorespiratory fitness were measured for adjustment for potential confounders. Adjusted linear regression models revealed a significant association of Leptin/Adiponectin (L/A) Ratio (baseline) with systolic BP (ß = 0.120; p < 0.034) and with diastolic BP (ß = 0.125; p < 0.036) at follow-up (full adjusted model). Leptin was associated with systolic BP at follow-up (ß = 0.102; p < 0.038) after adjustment for systolic BP at baseline, height, pubertal stage, socioeconomic status, adherence to Mediterranean diet, cardiorespiratory fitness, however, not independently of BMI. CONCLUSION: L/A ratio was positively associated with systolic BP and diastolic BP even after adjusting confounding variables. Therefore, a higher misbalance between leptin and adiponectin (higher L/A ratio) early adolescence may exert a negative effect BP levels in late adolescence regardless of several confounders factors.

High levels of adiponectin attenuate the detrimental association of adiposity with insulin resistance in adolescents.

BACKGROUND AND AIM: This study aimed to: i) examine the differences in insulin resistance (IR) across adiposity levels; and ii) ascertain whether high levels of adiponectin attenuate the detrimental association of adiposity with IR in adolescents. METHODS AND RESULTS: A total of 529 adolescents aged 12-18 years participated in this cross-sectional study (267 girls). Anthropometry and body adiposity parameters [body mass index (BMI), sum of skinfolds, body fat percentage (BF %) by bio-impedance analysis and waist circumference (WC)], were measured according to standardized procedures and categorized into age- and sex-specific quartiles. Socioeconomic status, pubertal stage and lifestyle determinants (Mediterranean diet adherence and cardiorespiratory fitness) were gathered and used as confounders. Serum adiponectin and IR (homeostasis model assessment of insulin resistance [HOMA-IR] estimated from fasting serum insulin and glucose were assessed. Analysis of covariance (ANCOVA) showed that HOMA-IR increased in a linear fashion throughout the quartiles of all adiposity measures (p < 0.001 for all), independently of age, sex, pubertal stage, socioeconomic status, adherence to the Mediterranean diet and cardiorespiratory fitness. Two-way ANCOVA showed that adolescents in the higher quartile of adiposity for BF%, BMI, WC and skinfolds sum (Q4) presented the highest adiponectin levels, and had 0.77 Standard Deviation (SD), 0.8 SD, 0.85 SD and 0.8 SD lower HOMA-IR, respectively (p < 0.01) than their low adiponectin group counterparts, after adjustments for potential confounders. CONCLUSION: Higher adiponectin levels may attenuate the detrimental association between adiposity and IR, particularly in subjects with higher adiposity.

Relationship between insulin resistance and adipocytokines: the mediator role of adiposity in children.

Background: Leptin and adiponectin interact with each other in the modulation of obesity and insulin resistance (IR) and it is also important to consider the role of cardiorespiratory and muscular fitness in these relationships.Aim: To analyse the relationship between IR with adipocytokines in children, and to test the mediation effect of %BF (percentage of body fat) in the association of IR with leptin, adiponectin, and L/A ratio.Subjects and methods: This cross-sectional study comprised a sample of 150 schoolchildren, aged 6-11 years, from school in Porto Alegre, Brazil. The following variables were evaluated: cardiorespiratory fitness (CRF), muscular fitness (MF), percentage of body fat (%BF), and biochemical variables (leptin, adiponectin, glucose, and insulin).Results: IR was associated with leptin and L/A ratio, after adjustments for age, sex, sexual maturation, and CRF. When adjusted for age, sex, sexual maturation, and MF, an association was found between IR with leptin and L/A ratio. Moreover, %BF was a mediator in the association between IR and leptin, as well as IR and L/A ratio, explaining 54% and 57% of these associations, respectively.Conclusion: Leptin and L/A ratio are positively associated with IR after adjustments. Also, %BF is a mediator in the associations between IR and leptin and L/A ratio.

Lifestyle patterns and endocrine, metabolic, and immunological biomarkers in European adolescents: The HELENA study.

OBJECTIVE: To evaluate the association of lifestyle patterns related to physical activity (PA), sedentariness, and sleep with endocrine, metabolic, and immunological health biomarkers in European adolescents. METHODS: The present cross-sectional study comprised 3528 adolescents (1845 girls) (12.5-17.5 years) enrolled in the Healthy Lifestyle in Europe by Nutrition in Adolescence Study. Cluster analysis was performed by including body composition, PA by accelerometry, self-reported sedentary behaviors, and sleep duration. We also measured endocrine, metabolic, and immunological biomarkers. RESULTS: Three-cluster solutions were identified: (a) light-PA time, moderate-vigorous-PA time and sedentary time, (b) light-PA time, moderate-vigorous-PA time, sedentary time and sleep time, (c) light-PA time, moderate-vigorous-PA time, sedentary time and body composition. In addition, each cluster solution was defined as: "healthy," "medium healthy," and "unhealthy" according to the presented rating. Analysis of variance showed that overall the healthiest groups from the three clusters analyzed presented a better metabolic profile. A decision tree analysis showed that leptin had a strong association with cluster 3 in both boys and girls, high-density lipoprotein cholesterol had the strongest association with clusters 1 and 3 in boys. Cortisol had the strongest association with cluster 1. HOMA index (homeostatic model assessment) and C3 showed a strong association with cluster 3 in girls. CONCLUSIONS: Our results support the existence of different interactions between metabolic health and lifestyle patterns related to PA, sedentariness, and sleep, with some gender-specific findings. These results highlight the importance to consider multiple lifestyle-related health factors in the assessment of adolescents' health to plan favorable strategies.

The combined association of adherence to Mediterranean diet, muscular and cardiorespiratory fitness on low-grade inflammation in adolescents: a pooled analysis.

PURPOSE: Low-grade inflammation leads to several metabolic disorders, and adherence to a Mediterranean diet (MedDiet), cardiorespiratory fitness (CRF), and muscular fitness (MF) has been considered important markers of metabolic healthy in youth. We investigated the combined association of adherence to Mediterranean diet, and muscular and cardiorespiratory fitness on high-sensitivity C-reactive protein (hs-CRP) in adolescents. METHODS: This is a cross-sectional analysis with 1462 adolescents (625 girls) aged 9-18 years from Colombia and Portugal. MedDiet was assessed by Kidmed questionnaire. Shuttle run test was used to assess CRF. MF was assessed by the standing long-jump and handgrip tests. High-sensitivity assays were used to obtain the hs-CRP level. RESULTS: Logistic regression shows that subjects with a low adherence to MedDiet and LowMF/LowCRF had a similar odds (OR = 2.3; 95% CI 1.2-4.0) as those with an optimal adherence to MedDiet and LowMF/LowCRF (OR = 2.3; 95% CI 1.2-5.0) of expressing high inflammatory profile when compared to those with an optimal adherence to MedDiet and HighMF/HighCRF. In addition, ANCOVA showed that subjects classified as high adherence to MedDiet and HighMF/HighCRF had, on average, the lowest levels of hs-CRP (F(7,1454) = 2.051 p = 0.04). CONCLUSION: The combination of optimal levels of CRF and MF and adherence to MedDiet is associated with lower hs-CRP. However, high MF and CRF seems to counteract the deleterious effect of having a low adherence to the MedDiet on hs-CRP levels.

Cardiorespiratory fitness and health-related quality of life in adolescents: A longitudinal analysis from the LabMed Physical Activity Study.

OBJECTIVE: The purpose of this study was to examine the longitudinal associations between cardiorespiratory fitness and health-related quality of life (HRQoL) in a sample of adolescents, and to determine whether changes in cardiorespiratory fitness were associated with HRQoL over a 2-year follow-up. METHODS: This is a longitudinal analysis with 571 Portuguese adolescents (274 boys and 297 girls) aged 12-18 years. HRQoL was measured with the Kidscreen-10 questionnaire; the 20 m shuttle-run was used to estimate cardiorespiratory fitness; socioeconomic status was assessed with the Family Affluence Scale; and pubertal stage was assessed with Tanner stages. Linear regression and analysis of covariance (ancovas) were used to examine the associations between cardiorespiratory fitness and HRQoL. RESULTS: HRQoL decreased over a 2-year period both in boys and girls (P < .05). Moreover, girls at baseline and at follow-up reported significantly lower HRQoL values than boys (between subjects P < .001). After adjustments for potential confounders, regression analyses showed significant cross-sectional associations between cardiorespiratory fitness and HRQoL both at baseline (B = 0.095; P = .023) and at follow-up (B = 0.090; P = .012). ancova showed that adolescents whose cardiorespiratory fitness decreased over time exhibited lower scores of HRQoL at follow-up, compared to those with persistent high cardiorespiratory fitness; this held after adjustments for age, sex, socioeconomic status, and pubertal stage. CONCLUSIONS: Changes in cardiorespiratory fitness during adolescence were associated with HRQoL over a 2-year period. This study suggests that improving cardiorespiratory fitness could be an important strategy in improving the HRQoL of adolescents.

Longitudinal associations between motor competence and different physical activity intensities: LabMed physical activity study.

An appropriated level of motor competence is essential for children´s healthy growth and development and a key factor in the promotion of lifelong active lifestyles and health. The purpose of this study was to examine associations between motor competence and different physical activity intensities (light, moderate, moderate-to-vigorous and vigorous physical activity), as well as total physical activity, over a two-year period, in adolescents. The sample comprised of 103 adolescents (13.49 ± 0.87 years, 53 girls), from the north of Portugal. Motor competence was evaluated with the body coordination test, Körperkoordination-Test-für-Kinder. Physical activity was objectively assessed with GT1M accelerometers (ActiGraph, Pensacola, FL, USA). Physical activity variables were expressed as proportions of accelerometer wear time. Regression analyses showed positive longitudinal associations between motor competence at baseline and moderate physical activity (B = 0.0033, p = 0.018), moderate-to-vigorous physical activity (B = 0.0052, p = 0.024) and total physical activity (B = 0.067, p = 0.040) at follow up, after adjustments for age, sex, the corresponding physical activity intensity at baseline, body mass index, pubertal stage and socioeconomic status. Our findings highlight the importance of motor competence development to promote moderate-to-vigorous physical activity during adolescence.

Cardiorespiratory Fitness Cut-Points are Related to Body Adiposity Parameters in Latin American Adolescents.

Background and Objectives: A deficiency exists in the criterion-referenced cut-points for field-based cardiorespiratory fitness (CRF) in Latin American youths. The aims of the present study were two-fold: (1) To identify the ability of CRF estimated by the 20-m shuttle-run test (20mSRT) to differentiate between "healthy" and "unhealthy" phenotypes (by adiposity) in adolescents; (2) to assess the association between obesity and relative peak oxygen uptake (VO2peak) in a large and diverse sample of Latin American youths. In total, 72,505 adolescents aged between 13 and 15 years were recruited from Chile and Colombia (47.5% girls). Materials and Methods: The waist circumference (WC) and waist-to-height ratio (WHtR) were used to identify body adiposity markers. CRF was measured using the 20mSRT (VO2peak). Receiver operating characteristic curves and logistic regression were used to determine the discriminatory ability of CRF to predict body adiposity parameters. Results: For boys and girls, VO2peak showed a significant predictive capacity to detect body fat (area under the curve [AUC] > 0.62). The sensitivity of VO2peak was medium (>63%) for all age- and sex-specific cut-points, with optimal cut-points in 13- to 15-year olds for obesity identified as 43.77 mL·kg-1·min-1 and 38.53 mL·kg-1·min-1 in boys and girls, respectively. Conclusions: According to these cut-points, adolescents with low CRF were more likely to be obese either by WC or WHtR. The CRF cut-points can be used as quantitative markers for a healthier body in Latin American adolescents.

Muscular fitness and cardiorespiratory fitness are associated with health-related quality of life: Results from labmed physical activity study.

BACKGROUND: Adolescents' physical fitness levels are an important indicator of their lifestyle and seem to have positive consequences in health-related quality of life (HRQoL). OBJECTIVE: The purpose of this study is to analyse the combined associations of cardiorespiratory fitness and muscular fitness with HRQoL and to assess the differences between HRQoL scores across groups of cardiorespiratory fitness and muscular fitness in Portuguese adolescents. DESIGN: This is a cross-sectional analysis with 567 Portuguese adolescents aged 12-18 years-old. METHODS: HRQoL was measured using the Kidscreen-10 questionnaire. Cardiorespiratory fitness was estimated with the 20-m shuttle-run test. Muscular fitness was evaluated using the handgrip and the standing long jump tests and a muscular fitness index was computed by means of standardized measures of both tests. Socioeconomic status was assessed using the Family Affluence Scale. Body composition (body mass and height) was measured according to standard protocols. Accelerometers were used to obtain objective physical activity time. Pubertal stage was assessed using Tanner stages. Adherence to the Mediterranean diet was assessed using the KIDMED index. Participants were divided into four groups based on low or high values of both cardiorespiratory and muscular fitness. Regression analysis, mediation analysis and ANCOVA were performed. RESULTS: HRQoL was positively associated with cardiorespiratory fitness (B = 0.112; p < 0.05) and muscular fitness score (B = 0.328 p < 0.05), after controlling for potential confounders. However, when both fitness variables were entered in the same model only cardiorespiratory fitness remained significantly associated with HRQoL (B = 0.093 p < 0.05). Cardiorespiratory fitness acted as a full mediator variable on the relationship between muscular fitness and HRQoL in adolescents (p < 0.05). ANCOVA showed that adolescents with high cardiorespiratory fitness/high muscular fitness exhibit better HRQoL scores when compared to those with low muscular fitness/low cardiorespiratory fitness and with those with low muscular fitness/high cardiorespiratory fitness (p < 0.05). CONCLUSIONS: In adolescents, the combination of high cardiorespiratory fitness and high muscular fitness was positively associated with a better HRQoL.

Cardiorespiratory Fitness and Blood Pressure: A Longitudinal Analysis.

OBJECTIVES: To examine the association between cardiorespiratory fitness and cardiovascular indices 2 years later, and to determine whether changes in cardiorespiratory fitness are associated with cardiovascular indices at a 2-year follow-up in adolescents. STUDY DESIGN: The sample comprised 734 adolescents (349 girls) aged 12-18 years followed for 3 years from the LabMed Physical Activity Study. Cardiorespiratory fitness was assessed by the 20-meter shuttle run test. Height, weight, waist circumference, and resting blood pressure (BP) were measured according to standard procedures. RESULTS: Regression analyses showed a significant inverse association between cardiorespiratory fitness at baseline and systolic BP (B = -0.126; P = .047) and rate pressure product (B = -29.94; P = .016), at follow-up after adjustments for age, sex, height, pubertal stage, socioeconomic status, and waist circumference. Significant differences were found between cardiorespiratory fitness groups (fit vs unfit) at baseline and systolic BP and rate pressure product at follow-up (P < .05 for all). Analysis of covariance showed a significant association between cardiorespiratory fitness changes and systolic BP (P = .024) and rate pressure product (P = .014), after adjustment for age, sex, height, pubertal status, socioeconomic status, and waist circumference. CONCLUSIONS: Changes in cardiorespiratory fitness during adolescence were associated with cardiovascular indices over a 2-year period. Adolescents with persistently low levels of cardiorespiratory fitness exhibited the highest levels of systolic BP and rate pressure product.

Low-grade inflammation and muscular fitness on insulin resistance in adolescents: Results from LabMed Physical Activity Study.

BACKGROUND: Low muscular fitness (MF) and low-grade inflammation has been linked to insulin resistance (IR). OBJECTIVE: To evaluate the associations between MF and a clustered score of inflammatory biomarkers on IR and to investigate the combined impact of MF and inflammation on IR in adolescents. METHODS: This is a cross-sectional analysis with 529 adolescents (267 girls) aged 12 to 18 years. Pubertal stage, socioeconomic status, adherence to the Mediterranean diet, cardiorespiratory fitness, and waist circumference were assessed. Standing long-jump and isometric handgrip dynamometry were used as indicators of MF. Continuous score of clustered inflammatory biomarkers (InflaScore) (sum of Z-scores of C-reactive protein, C3, C4, fibrinogen, and leptin) and IR (homeostasis model assessment of insulin resistance [HOMA-IR] estimated from fasting serum insulin and glucose) were assessed. RESULTS: HOMA-IR and fasting insulin were positively associated with InflaScore and negatively associated with MF, independently of age, sex, pubertal stage, socioeconomic status, adherence to the Mediterranean diet, cardiorespiratory fitness, and waist circumference. Adolescents classified as High InflaScore/Unfit showed significantly higher HOMA-IR when compared than those with High InflaScore/Fit and those with Low InflaScore/Fit (F(3,519) = 4.761, P < .003), after adjustments for potential confounders. Unfit adolescents with high InflaScore had the highest odds of expressing high HOMA-IR (odds ratio, OR = 2.40, 95% confidence interval [CI]: 1.2-5.6) and insulin risk (2.53 95% CI, 1.5-5.9) when compared to those of the Low InflaScore/Fit group, after adjustments for potential confounders. CONCLUSION: Higher levels of MF seem to minimize the deleterious effect of inflammation on IR.

Changes in muscular fitness and its association with blood pressure in adolescents.

The aims of this study were to examine the longitudinal association between muscular fitness (MF) and blood pressure (BP) 2 years later, and to determine whether changes in MF over a 2-year period were associated with BP at follow-up, in adolescents. The sample comprised 734 youths (349 girls) aged from 12 to 18 years. MF was assessed with the standing long jump and handgrip tests. Socioeconomic status, pubertal stage, waist circumference, resting BP, and cardiorespiratory fitness were measured according to standard procedures. Regression analyses showed a significant inverse association between MF at baseline and systolic BP (ß = - 0.072; p = 0.032) and rate pressure product (ß = - 0.124; p < 0.001) at follow-up, after adjustments for age, sex, height, pubertal stage, and socioeconomic status. However, when analyses were further adjusted for waist circumference and cardiorespiratory fitness, these associations did not remain significant. Adolescents with persistently high and increasing MF exhibited the lowest levels of diastolic BP (F(3, 721) = 3.814, p = 0.018) and systolic BP (F(3, 721) = 3.908, p = 0.014) when compared to those with persistent low MF after adjustment for age, sex, height, socioeconomic status, cardiorespiratory fitness, and waist circumference.Conclusion: This study suggests that persistent greater and increasing MF in youth are associated with lower levels of BP across the adolescence. What is Known: • Currently, there is a growing interest on the health benefits of muscular fitness. • Cross-sectional studies have identified an association between muscular fitness and blood pressure in adolescents. What is New: • Changes in muscular fitness during adolescence were associated with systolic and diastolic BP over a 2-year period. • Adolescents with persistently low muscular fitness exhibited the highest levels of diastolic and systolic BP.