Cardiorespiratory Fitness In Youth Research Articles

Physical Activity Intensity and Cardiometabolic Risk in Youth

To determine the association between physical activity (PA) intensities and cardiometabolic risk factors in youth. Cross-sectional study using data from the 2008 Healthy Hearts Prospective Cohort Study of Physical Activity and Cardiometabolic Health in Youth. Rural and urban communities in Alberta, Canada. A convenience sample of 605 youth aged 9 to 17 years. Youth were on average aged 12.1 years, 248 were boys (41%), and 157 were overweight or obese (26%). Actical accelerometer-measured PA intensity. The primary outcome was body mass index (calculated as weight in kilograms divided by height in meters squared) z score. Secondary outcome measures included waist circumference, systolic blood pressure, and cardiorespiratory fitness (maximal oxygen consumption [[Vdot]O2max]). Body mass index z score, waist circumference, and systolic blood pressure decreased and [Vdot]O2max increased in a dose-response manner across tertiles of vigorous PA (adjusted P < .001). No significant differences in cardiometabolic risk factors were seen across tertiles of moderate or light PA in multivariable analyses. Achieving more than 7 minutes of vigorous PA daily was associated with a reduced adjusted odds ratio of overweight status (0.56; 95% CI, 0.33-0.95) and elevated systolic blood pressure (0.36; 95% CI, 0.16-0.79). The odds of overweight status and elevated blood pressure decreased with increasing time and intensity of PA. Only vigorous PA was consistently associated with lower levels of waist circumference, body mass index z score, systolic blood pressure, and increased cardiorespiratory fitness in youth. These findings underscore the importance of vigorous PA in guidelines for children and adolescents.

Bicycling to school is associated with improvements in physical fitness over a 6-year follow-up period in Swedish children

ObjectiveTo examine whether modes of commuting to school at baseline and changes in commuting were related to 6-year changes in cardiorespiratory fitness in youth. MethodsA total of 262 (142 girls) Swedish children (9years at entry) were measured at baseline (1998/9) and follow-up (2004/5). Mode of commuting to school was assessed by questionnaire and fitness by a maximal bicycle test. ResultsAt baseline, 34% of children used passive modes of commuting (e.g., car, motorcycle, bus, train), 54% walked, and 12% bicycled to school. Six years later the percentage of bicyclists increased 19% and the percentage of walkers decreased 19%. On average, children who bicycled to school increased their fitness 13% (p=0.03) more than those who used passive modes and 20% (p=0.002) more than those who walked. Children who used passive modes or walked at baseline and bicycled to school at 6years later increased their fitness 14% (p=0.001) more than those who remained using passive modes or walking at follow-up. ConclusionsImplementing initiatives that encourage bicycling to school may be a useful strategy to increase cardiorespiratory fitness of children.

Screen time and passive school travel as independent predictors of cardiorespiratory fitness in youth

ObjectiveThe most prevalent sedentary behaviours in children and adolescents are engagement with small screen media (screen-time) and passive travel (by motorised vehicle). The objective of this research was to assess the independence of these behaviours from one another and from physical activity as predictors of cardiorespiratory fitness in youth. MethodsWe measured cardiorespiratory fitness in n=6819 10–16year olds (53% male) who self-reported their physical activity (7-day recall) school travel and screen time habits. Travel was classified as active (walking, cycling) or passive; screen time as <2h, 2–4h or >4h. ResultsThe multivariate odds of being fit were higher in active travel (Boys: OR 1.32, 95% CI: 1.09–1.59; Girls: OR 1.46, 1.15–1.84) than in passive travel groups. Boys reporting low screen time were more likely to be fit than those reporting >4h (OR 2.11, 95% CI: 1.68–2.63) as were girls (OR 1.66, 95% CI: 1.24–2.20). These odds remained significant after additionally controlling for physical activity. ConclusionPassive travel and high screen time are independently associated with poor cardiorespiratory fitness in youth, and this relationship is independent of physical activity levels. A lifestyle involving high screen time and habitual passive school travel appears incompatible with healthful levels of cardiorespiratory fitness in youth.

Associations between cardiorespiratory fitness, physical activity and clustered cardiometabolic risk in children and adolescents: the HAPPY study

Clustering of cardiometabolic risk factors can occur during childhood and predisposes individuals to cardiometabolic disease. This study calculated clustered cardiometabolic risk in 100 children and adolescents aged 10-14 years (59 girls) and explored differences according to cardiorespiratory fitness (CRF) levels and time spent at different physical activity (PA) intensities. CRF was determined using a maximal cycle ergometer test, and PA was assessed using accelerometry. A cardiometabolic risk score was computed as the sum of the standardised scores for waist circumference, blood pressure, total cholesterol/high-density lipoprotein ratio, triglycerides and glucose. Differences in clustered cardiometabolic risk between fit and unfit participants, according to previously proposed health-related threshold values, and between tertiles for PA subcomponents were assessed using ANCOVA. Clustered risk was significantly lower (p < 0.001) in the fit group (mean 1.21 ± 3.42) compared to the unfit group (mean -0.74 ± 2.22), while no differences existed between tertiles for any subcomponent of PA. Conclusion These findings suggest that CRF may have an important cardioprotective role in children and adolescents and highlights the importance of promoting CRF in youth.

Associations of Cardiorespiratory Fitness in Children and Adolescents With Physical Activity, Active Commuting to School, and Screen Time.

The objective of this study was to analyze associations of cardiorespiratory fitness (CRF) with physical activity, time spent watching television and using computer, mode of commuting to school (CS), and adiposity, by gender. Participants were 1708 students (53.8% girls), aged 11 to 19 years. CRF was evaluated with a 20-meter shuttle-run test using VO2max by previously published equation. Maturation stages determined by Tanner's criteria, body mass index, and skinfolds were measured, and a questionnaire used to assess socioeconomic status, PA, television and computer time, and mode of CS. We conducted a regression analysis using CRF as the dependent variable. CRF was independent and positively associated with physical activity [β = 0.338 (95% CI = 0.119; 0.188); P < .001] and with maturation [β = -0.876 (95% CI = 0.666; 1.087); P < .001]; independent and negatively associated with television time [β = -0.003 (95% CI = -0.005; -0.002); P < .001] and adiposity [β = -0.068 (95% CI = -0.076; -0.060); P < .001]. CRF was positively associated with CS [β = 0.337; (95% CI = 0.014; 0.741); P = .014]. No associations were found for computer time. These findings suggest that increasing overall physical activity levels through interventions in different domains such as active CS, reducing sedentary activities, such as television time, might be effective strategies for improving CRF in youth.

The relationship between active travel to school and health-related fitness in children and adolescents: a systematic review.

BackgroundActive travel to school (ATS) has been identified as an important source of physical activity for youth. However, the relationship between ATS and health-related fitness (HRF) among youth remains unclear.MethodsA systematic search of seven electronic databases (EMBASE, OVID MEDLINE, PsycINFO, PubMed, Scopus, SPORTDiscus and TRIS on line) was conducted in December 2009 and studies published since 1980 were considered for inclusion.ResultsTwenty seven articles were identified that explored the relationship between ATS and the following aspects of HRF: weight status/body composition, cardiorespiratory fitness, muscular fitness and flexibility. Forty-eight percent of the studies that examined the relationship between ATS and weight status/body composition reported significant associations, this increased to 55% once poor quality studies were removed. Furthermore, the findings from five studies, including one longitudinal study, indicate that ATS is positively associated with cardiorespiratory fitness in youth. However, the evidence for the relationships between ATS and muscular fitness or flexibility is equivocal and limited by low study numbers.ConclusionsThere is some evidence to suggest that ATS is associated with a healthier body composition and level of cardiorespiratory fitness among youth. Strategies to increase ATS are warranted and should be included in whole-of-school approaches to the promotion of physical activity.

Are We There Yet? Pediatric Screening for Inflammatory Biomarkers and Low Cardiorespiratory Fitness to Identify Youth at Increased Risk of Cardiovascular Disease

Are We There Yet? Pediatric Screening for Inflammatory Biomarkers and Low Cardiorespiratory Fitness to Identify Youth at Increased Risk of Cardiovascular Disease

US Youth Cardiorespiratory Fitness Levels: Challenges and Solutions—Reply

US Youth Cardiorespiratory Fitness Levels: Challenges and Solutions—Reply

US Youth Cardiorespiratory Fitness Levels: Challenges and Solutions

US Youth Cardiorespiratory Fitness Levels: Challenges and Solutions

Cardiorespiratory Fitness in Youth: Relationship to Insulin Sensitivity and β‐Cell Function

We examined whether the relationship between cardiorespiratory fitness (CRF) and insulin sensitivity (IS)/secretion is independent of adiposity in healthy African-American (n = 65) and white (n = 57) youth. IS and beta-cell function were evaluated by a 3-hour hyperinsulinemic-euglycemic and a 2-hour hyperglycemic (12.5 mM) clamp, respectively. Total fat was measured by DXA and abdominal fat with computed tomography. CRF (peak volume of oxygen) was measured using a graded maximal treadmill test. Independent of race, CRF was inversely (p < 0.05) related to total and abdominal fat, fasting insulin and first phase insulin secretion, and positively (p < 0.05) related to IS. When subjects were categorized into low (< or = 50th) and high (> 50th) CRF groups, IS was significantly (p < 0.05) higher in the high compared with the low CRF group independently of race. Furthermore, first and second phase insulin secretion were lower (p < 0.05) in the high CRF group in comparison with the low CRF group in both races. However, in multiple regression analyses CRF was not (p > 0.05) an independent predictor of IS and acute insulin secretion after accounting for total adiposity. Our findings demonstrate that low CRF is associated with decreased IS compensated by higher insulin secretion in both African-American and white youth. However, this relationship disappears after adjusting for differences in adiposity, suggesting that the association between fitness and IS is mediated, at least in part, through fatness.

Declining Cardiorespiratory Fitness in Youth: Fact or Supposition?

Declining Cardiorespiratory Fitness in Youth: Fact or Supposition?