Physical activity throughout adolescence and body composition at 18 years: 1993 Pelotas (Brazil) birth cohort study

Abstract

BackgroundAdolescence is a period of accelerated development and increases in body composition. Physical activity (PA) practice has been associated with the development of major components of body composition (bone, muscle and fat). However, the longitudinal effects of PA of different intensities during adolescence are still not well understood. Thus, the main goal this study has investigate the association between practice of moderate- and vigorous-intensity physical activity throughout adolescence and body composition, specifically lean mass (LM) and fat mass (FM), at age 18.MethodsIn this cohort study, physical activity was measured at 11, 15 and 18 years, using questionnaires. Thresholds of 300, 150 and 75 min per week, were used for MVPA, moderate- and vigorous-intensity physical activity, respectively. Consistent physical activity was defined as reaching the thresholds at the three follow-ups. FM and LM at age 18 were assessed by DXA and expressed as fat mass (FMI) and lean mass (LMI) indexes. To verify the association between the trajectories of MVPA, moderate- and vigorous-intensity physical activity in adolescence and FM and LM at 18, multivariate analyses were performed through multiple linear regressions adjusted for co-variables.ResultsA total of 3,176 adolescents were evaluated. The consistent practice of moderate- and vigorous-intensity physical activity according to thresholds during adolescence were directly related to the LMI in boys (moderate-intensity - β = 0.40 and CI95 % 0.13; 0.68 and vigorous-intensity - β = 0.95 and CI95 % 0.69; 1.21) and girls (Moderate-intensity - β = 0.23 and CI95 % 0.02; 0.45 and vigorous-intensity - β = 0.80 and CI95 % 0.29; 1.32). Practice of vigorous-intensity physical activity alone showed to be inversely associated with the FMI in boys (β = -0.53 and CI95 % -0.96;–0.10).ConclusionConsistent physical activity practice during adolescence was associated with greater lean mass in both sexes. In boys, vigorous-intensity physical activity was associated with less fat mass.

Agreement between body mass index and the sum of skinfolds in adolescents with different levels of physical activity

“…this hypothesis is supported by the results of a prior study in which adolescents who completed scheduled PA for one year presented with BMI stability, lean mass increase, and fat mass reduction in the triceps region [7]. therefore, the findings of the present study, and of other studies mentioned above [2,7,10,24] reinforce the hypothesis that BMI measurements must be carefully interpreted especially among physically active adolescents. due to the risk of misclassifying male adolescents who meet PA requirements as being overweight, the use of a more accurate assessment of body composition is strongly recommended.…”

“…this finding is consistent with previous systematic reviews which found that, regardless of the method used to estimate adolescents' body fat, BMI measurements' sensitivity to detect fat mass is low [4] and that PA is inversely related to fat mass but not to BMI [12]. Additionally, researchers controlling for physical growth and biological maturation found that PA explains 21% of the increase in lean muscle mass [10] and that physically active adolescents who maintain such condition present with higher amounts of lean mass in comparison with their insufficiently active peers [24]. Conversely, in a population study performed with adults with the same BMI, it was found that those that were physically active presented a greater percentage of body fat [2].…”

Associations between muscle mass, physical activity and dietary behaviour in adolescents

“…In contrast, The Healthy Lifestyle in Europe by Nutrition in Adolescence study failed to find an association between physical activity and fat-free mass in Spanish adolescents aged 12.5-17.5 years (33). Moreover, longitudinal studies observed that habitual physical activity had a significant independent influence on the growth of lean body mass during adolescence (34,35). Taken together, all of these studies have not considered dietary factors as potential confounding variables, which may be one of the reasons leading to the inconsistent results.…”

Self‐reported physical activity during leisure time was favourably associated with body composition in Norwegian adolescents

“…However, it has been reported that even a small difference in lean mass may have a substantial effect on increase in fat mass, since muscles are particularly important for oxidisation of fat . Another study found that those with higher lean mass could have higher resting metabolism through the effect of increased muscle mass . The effect of regular physical activity on lean mass is, therefore, important when it comes to preventing overweight and obesity.…”