Virgílio Viana Ramires, Samuel Carvalho Dumith and Helen Gonçalves
Physical activity (PA) practice has been inversely associated to body fat (BF) and recommended as a way to reduce and prevent obesity. The objective of this study was to conduct a systematic review on the association of PA and BF in adolescence.
The review includes 18 longitudinal studies found in the PubMed database, comprising papers published from January 1990 to July 2014. Studies assessing BF only through body mass index were excluded.
Among the outcomes analyzed, waist circumference, skinfolds, and absolute and relative fat mass measurement were identified. Questionnaires were the more predominant way to evaluate PA. Most studies showed that PA promotes a protective effect against a higher BF gain.
It was concluded that PA has a protective effect against BF with differences between the genders and according to the BF marker or measurement assessed; higher intensity PA leads to a greater effect against BF gain in both genders; and the maintenance or increase of PA level on BF observed through analysis of change in PA level yielded more consistent findings in the relation between PA and BF.
Pedro Curi Hallal, Felipe Fossati Reichert, Fernando Vinholes Siqueira, Samuel Carvalho Dumith, Juliano Peixoto Bastos, Marcelo Cozzensa da Silva, Marlos Rodrigues Domingues, Mario Renato Azevedo and Ulf Ekelund
The objective of this study was to evaluate physical activity (PA) levels in adults and their association with sex, age, and education level across categories of body mass index (BMI).
We conducted a population-based, cross-sectional study including 3100 individuals age ≥20 years living in Pelotas, Brazil. PA was assessed using the leisure-time section of the long International Physical Activity Questionnaire. “No PA” was defined as zero minutes of activity/week; “insuffcient PA” was defined as <150 minutes of activity/week; “high PA” was defined as ≥500 minutes of activity/week. BMI was categorized into normal (<25 kg/m2), overweight (25–29.9 kg/m2), and obesity (≥30 kg/m2).
The prevalence of insufficient PA was 71.6% among normal BMI subjects, 71.3% among overweight individuals, and 73.7% among obese ones (P = .67). No PA and high PA were also not associated with BMI. The associations between sex, age, and education level and PA levels tended to be stronger among normal-weight individuals compared with overweight and obese individuals. Among the obese, most associations were not significant. Among normal-weight individuals, higher PA levels were observed in men, young adults, and those with higher education.
Variables associated with leisure-time PA differed between normal-weight, overweight, and obese individuals. Studies on PA correlates might benefit from stratifying by BMI.
Pedro C. Hallal, Samuel Carvalho Dumith, Felipe Fossati Reichert, Ana M.B. Menezes, Cora L. Araújo, Jonathan C.K. Wells, Ulf Ekelund and Cesar G. Victora
To explore cross-sectional and longitudinal associations between self-reported and accelerometry-based physical activity (PA) and blood pressure (BP) between 11 and 14 years of age.
Prospective birth cohort study in Pelotas, Brazil. Participants were 427 cohort members who were followed up with at 11, 12, and 14 years of age, and had questionnaire data on PA and BP at 11 and 14 years, as well as accelerometry and questionnaire data on PA at 12 years. Outcome measures were continuous systolic and diastolic BP at 14 years, and change in BP from 11 to 14 years.
PA was unrelated to systolic BP in any analyses. PA measured by accelerometry at 12 years, but not questionnaire-derived PA, was inversely associated with diastolic BP at 14 years of age in fully adjusted models. Those who exceeded the 300-minutes PA threshold at all 3 visits had a 2.6 mmHg lower mean increase in DBP from 11 to 14 years compared with those classified below the threshold in all visits.
Accelerometry-based PA was longitudinally inversely associated with diastolic BP. This finding was not evident when analyzing self-reported PA at a given age, suggesting a possible underestimation of the association when using subjective data.
Samuel Carvalho Dumith, Virgílio Viana Ramires, Matheus Alves Souza, Daniel Souza Moraes, Fabrício Godoy Petry, Eduardo Soldera Oliveira, Sandro Viana Ramires and Pedro C. Hallal
Physical fitness is strongly associated with several positive health indicators among adolescents. However, its association with body mass index status is inconsistent. The aim of this study was to explore the association between overweight/obesity and physical fitness among children and adolescents.
The design consisted of a cross-sectional study comprising 519 Brazilian students age 7 to 15 years. BMI status was assessed according to sex- and age-specific growth charts. Physical fitness was assessed using 8 tests: sit-and-reach, stationary long jump, 1-minute curl-up, modified pull-up, medicine-ball throw, 9-minute run, 20-m run, and 4-m shuttle-run.
Prevalence of overweight and obesity was 24% and 12%, respectively. Boys performed better than girls in all tests, except flexibility. Normal weight students performed better than overweight and obese students in all tests, except the sit-and-reach and the medicine-ball throw. Cardiorespiratory fitness had the strongest association with BMI status. The prevalence of obese subjects classified as “most fit” was less than 10%.
Higher values of body mass index were associated with declines in physical fitness, independent of age. The majority of obese children and adolescents and almost a half of those overweight were classified in the third tertile of physical fitness (least fit).