Vigorous physical activity and low-grade systemic inflammation in adolescent boys and girls.
ABSTRACT The association between physical activity (PA) and inflammation has been established in adults, yet little is known about this relationship in youth. This study examined the relationship between vigorous PA and C-reactive protein (CRP) in adolescents.
Data were available for 1 520 adolescents, aged 13 and 16 years, in a province-wide survey of a representative sample of youth in Québec, Canada. Participants completed questionnaires assessing VPA, pubertal stage, body image, and health problems; they provided a fasting blood sample for CRP; and they had height and weight measured.
In sex-specific multivariable logistic regression models, VPA was protective of elevated CRP in boys (OR=0.60, 95%CI=0.37-0.99) independent of weight status, pubertal stage, anti-inflammatory/antibiotic medication, and smoking. CRP and physical activity were not related in girls (OR=1.12, 95%CI=0.69-1.82).
In addition to many known health benefits of VPA, the current findings provide evidence that VPA may protect against low-grade systemic inflammation in boys. These data provide further support for the importance of promoting healthy PA levels in youth.
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ABSTRACT: (I have permission to e-mail copies of this article from my university e-mail account. If you wish to receive a copy of this article, please e-mail your request to email@example.com). Purpose: There is little scholarship on physical activity among children within outdoor spaces and work is needed to advance the design of these spaces from "best practices" towards evidence-based design. This project examined how playground feature density relates to children's physical activity. Design . We used the System for Observing Play and Leisure Activity to observe children's physical activity. Setting . We observed children during school recess on 24 school grounds in the Denver metropolitan area of Colorado, in spring of 2010 and 2011. Subjects . A total of 31,069 observations were made from an estimated 9900 children aged 5 to 12. These were aggregated and analyzed in 397 playground zones. Measures: We examined utilization, the number of children present in a particular activity zone during an observation, and the percentage of children engaged in moderate to vigorous physical activity as they relate to the density of constructed features on school playgrounds. Analysis: Ordinary least-squares linear regression model assessed the relationship between playground feature density and the utilization and moderate to vigorous physical activity. Results: Significant positive associations were observed between utilization and feature density among all children (β = .20; p < .001) and a statistically significant but small association was observed between moderate to vigorous physical activity and feature density for girls (β = .12; p = .013), but not for boys. Conclusion: This analysis contributes to evidence that design features of play spaces may influence children's behavior within school grounds.American journal of health promotion: AJHP 08/2013; 28(6). DOI:10.4278/ajhp.121116-QUAN-566 · 2.37 Impact Factor
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ABSTRACT: This study assessed the changes in time spent in moderate to vigorous physical activity (MVPA) on fat depots, insulin action, and inflammation. Longitudinal data were generated from 66 Hispanic adolescents (15.6±1.1 yr; BMI percentile 97.1±3.0) who participated in a 16-wk nutrition or nutrition+exercise intervention. There were no effects of the intervention on PA, but there were inter-individual changes in PA. For purposes of this analysis, all intervention groups were combined to assess how changes in PA during 16 wk affected changes in adiposity, insulin action, and markers of inflammation. MVPA was assessed by 7-day accelerometry, total body fat via DXA, liver fat by MRI, and insulin, glucose and HOMA-IR via a fasting blood draw. A repeated measures ANCOVA was used to assess the effect of MVPA on fat depots, insulin action, and inflammatory markers. Sixty-two percent of participants increased MVPA (mean increase, 19.7±16.5 min/day) and 38% decreased MVPA (mean decrease, 10.7±10.1 min/day). Those who increased MVPA by as little as 20 min per day over 16 wk, compared to those who decreased MVPA, had significant reductions in liver fat (-13% vs. +3%; P=0.01), leptin levels (-18% vs. +4%; P=0.02), and fasting insulin (-23% vs. +5%; P=0.05). These findings indicate that a modest increase in MVPA can improve metabolic health in sedentary overweight Hispanic adolescents.Journal of Exercise Physiology Online 04/2012; 15(2):40-54.
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ABSTRACT: Chronic, systemic inflammation is an independent risk factor for several major clinical diseases. In obesity, circulating levels of inflammatory markers are elevated, possibly due to increased production of pro-inflammatory cytokines from several tissues/cells, including macrophages within adipose tissue, vascular endothelial cells and peripheral blood mononuclear cells. Recent evidence supports that adipose tissue hypoxia may be an important mechanism through which enlarged adipose tissue elicits local tissue inflammation and further contributes to systemic inflammation. Current evidence supports that exercise training, such as aerobic and resistance exercise, reduces chronic inflammation, especially in obese individuals with high levels of inflammatory biomarkers undergoing a longer-term intervention. Several studies have reported that this effect is independent of the exercise-induced weight loss. There are several mechanisms through which exercise training reduces chronic inflammation, including its effect on muscle tissue to generate muscle-derived, anti-inflammatory 'myokine', its effect on adipose tissue to improve hypoxia and reduce local adipose tissue inflammation, its effect on endothelial cells to reduce leukocyte adhesion and cytokine production systemically, and its effect on the immune system to lower the number of pro-inflammatory cells and reduce pro-inflammatory cytokine production per cell. Of these potential mechanisms, the effect of exercise training on adipose tissue oxygenation is worth further investigation, as it is very likely that exercise training stimulates adipose tissue angiogenesis and increases blood flow, thereby reducing hypoxia and the associated chronic inflammation in adipose tissue of obese individuals.Sports Medicine 03/2013; 43(4). DOI:10.1007/s40279-013-0023-3 · 5.32 Impact Factor