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  • Author: Teresa Helena Macedo da Costa x
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Julia Aparecida Devide Nogueira and Teresa Helena Macedo da Costa

Background:

Body weight and composition are determined by genotype, environment, and energy balance. Physical activity or sedentary behavior have different associations with body weight, fat mass, and fat-free mass, a relationship that is not clear in adolescents. The aim of this study was to test the associations between gender, physical activity, sedentary behavior, and body composition in physically active adolescents.

Methods:

Weight, height, and skinfold thickness were measured in 326 physically active boys and girls age 11 to 15 years. All subjects answered a questionnaire assessing their usual daily activities for the last month. Time spent on each activity was used to estimate the physical activity level (PAL).

Results:

PAL was associated with body composition after adjustment for age and maturation, with differences between genders. For boys, PAL was positively and significantly associated with body mass index (BMI) and fat-free mass index (β= 0.14 and 0.15, respectively). For girls, PAL was negatively and significantly associated with BMI and fat mass index (β= −0.11 and −0.75, respectively). Sedentary behavior, expressed by hours of TV, videogame, and computer use, was not associated with any body-composition outcome for either gender.

Conclusion:

The accumulated amount of physical activity, but not of sedentary behavior, was related to body composition in active adolescents.

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Laís Monteiro Rodrigues Loureiro, Caio Eduardo Gonçalves Reis and Teresa Helena Macedo da Costa

Coffee is one of the most consumed beverages in the world, and it can improve insulin sensitivity, stimulating glucose uptake in skeletal muscle when adequate carbohydrate intake is observed. The aim of this review is to analyze the effects of coffee and coffee components on muscle glycogen metabolism. A literature search was conducted according to Preferred Reporting Items for Systematic Reviews and Meta-Analysis, and seven studies were included, that explored the effects of coffee components on various substances and signaling proteins. In one of the studies with humans, caffeine was shown to increase glucose levels, Ca2+/calmodulin-dependent protein kinase phosphorylation, glycogen resynthesis rates, and glycogen accumulation after exercise. After intravenous injection of caffeine in rats, caffeine increased adenosine monophosphate-activated protein kinase (AMPK) and acetyl-CoA carboxylase (ACC) phosphorylation, and glucose transport. In in vitro studies, caffeine raised AMPK and ACC phosphorylation, increasing glucose transport activity and reducing energy status in rat muscle cells. Cafestol and caffeic acid increased insulin secretion in rat beta cells and glucose uptake into human muscle cells. Caffeic acid also increased AMPK and ACC phosphorylation, reducing the energy status and increasing glucose uptake in rat muscle cells. Chlorogenic acid did not show any positive or negative effect. The findings from this review must be taken with caution due to the limited number of studies on the subject. In conclusion, various coffee components had a neutral or positive role in the metabolism of glucose and muscle glycogen, whereas no detrimental effect was described. Coffee beverages should be tested as an option for athletes’ glycogen recovery.