Biomedical subjects

C Platat

Publications and source records attributed to C Platat.

3 recordsLinked to original sources

PubMed2006

Habitual physical activity, physical fitness and heart rate variability in preadolescents.

The amount and type of physical activity (PA) appropriate in youth for optimal health is still being discussed. The purpose of this study on 12-year-old preadolescents is to evaluate the association of two PA patterns, corresponding to different exercise intensities, with some health-related indexes. PA was evaluated by triaxial accelerometry in 67 student subjects, who were successively classified according to 1) their usual participation or not in moderately intense (> 4 metabolic equivalents, METs) activities (either in daily life or in leisure activities) for at least 210 min a week (4 M (210)); and 2) the habitual practice or not of more intense activities (> 6 METs) for at least 60 min a week (6 M (60)). Health-related indexes consisted of cardiopulmonary (maximum oxygen uptake, V.O 2max), muscular (lower limb strength) fitness parameters and vagal-related indexes of heart rate (HR) variability (HRV), such as the HF/(LF+HF) ratio (where HF and LF stand for high and low frequency power). HR was recorded in the supine position after 15 min of quiet rest, and HRV indexes were calculated in 5-min segments. Energy expenditure due to PA was not significantly associated with any health-related index. Reaching 4 M (210) was associated with both higher estimated V.O 2max (p < 0.05) and higher muscular strength indexes (p < 0.05) but not with enhanced HRV indexes. Subjects who reached 6 M (60) had higher estimated V.O2max (p < 0.05) and higher HF/(LF+HF) (p < 0.05). Our results show that regular moderately intense activities are sufficient to influence physical fitness but suggest that more intense activities are necessary to observe more favorable HRV vagal-related indexes.

Child↗

PubMed2006

Relationships of physical activity with metabolic syndrome features and low-grade inflammation in adolescents.

AIMS/HYPOTHESIS: Physical activity has beneficial effects on symptoms of the metabolic syndrome and low-grade inflammation in adults. These associations have rarely been studied in adolescents. Moreover, it has not been established whether they depend on adiposity, fat localisation and adipokines. SUBJECTS, MATERIALS AND METHODS: We used cross-sectional data of 640 12-year-old adolescents participating in the Intervention Centred on Adolescents' Physical Activity and Sedentary Behaviour Study (ICAPS). Weight, height, body fat mass and WHR were measured. Metabolic syndrome components, two inflammatory markers (IL-6 and C-reactive protein), plasma leptin, adiponectin and soluble TNF-alpha receptor 1 (sTNF-alpha R1) were determined. Insulin resistance was estimated by homeostasis model assessment (HOMA) and energy expenditure due to organised leisure-time physical activity (PAE) assessed by questionnaire. RESULTS: The metabolic syndrome was present in 5.8% of the adolescents. After adjustment for sex, sexual maturity and socio-economic status, a beneficial relationship between PAE and all metabolic syndrome features was found, but only the associations with HOMA and IL-6 were independent of body fat mass and WHR. Adjusted means from the lowest to the highest tertile of PAE were 1.99, 1.80 and 1.78 for HOMA (p=0.04), and 0.88, 0.69 and 0.70 pg/ml for IL-6 (p=0.02). PAE was inversely associated with leptin, independently of body fat mass and WHR (p<10(-2)), but not with adiponectin or sTNF-alpha R1. Further adjustment for adipokines did not change the relationships of PAE with HOMA and IL-6. CONCLUSIONS/INTERPRETATION: In adolescents, physical activity is inversely related to HOMA and IL-6, independently of adiposity and fat localisation. These relationships are not accounted for by adipokines.

Adipocytes↗

PubMed2006

ICAPS: a multilevel program to improve physical activity in adolescents.

OBJECTIVES: ICAPS (Intervention Centred on Adolescents' Physical activity and Sedentary behaviour) is aimed at preventing excessive weight gain and cardiovascular risk in adolescents by promoting physical activity (PA) with an emphasis on recreational and daily-life PA, with a lifelong perspective. DESIGN: Randomized study designed to last for four years. Study cohort constituted of 954 first-level students (91% of eligible pupils), aged 11.7 +/- 0.6 y (mean +/- SD) from four pairs of schools randomly selected in eastern France, after sociogeographical stratification. In each pair, intervention status was randomised at school-level. The program, not limited to school settings, involves multiple partners with three objectives: 1) changing attitudes through debates and access to attractive activities during breaks and after-school hours, 2) encouraging social support, 3) providing environmental conditions that enable PA. Adapted times and places, open participation, emphasis on fun, meeting with others and absence of competitive aspects are used to reduce usual barriers to PA. Accessibility and safety are permanent concerns. RESULTS: Prevalence of overweight was 23.7%. High participation rates were attained (50% participated in at least one weekly activity). At six-month, the proportion of intervention adolescents not performing supervised PA out of academic PA was reduced by half (36% to 17% vs 42% to 42% in controls P < 10-4); the proportion of those spending > 3 h/day in sedentary occupations decreased (34% to 28% vs 27% to 36%; P < 10-4). CONCLUSION: These data demonstrate the feasibility of implementing a multilevel PA intervention program in adolescents. Six-month results document increased PA and decreased sedentary behaviour.

Adolescent↗