Aerobic Fitness, Not Energy Expenditure, Influences Subsequent Increase in Adiposity in Black and White Children

Abstract

ABSTRACT. Background. Low levels of energy expenditure and aerobic fitness have been hypothesized to be risk factors for obesity. Longitudinal studies to determine whether energy expenditure influences weight gain in whites have provided conflicting results. To date, no studies have examined this relationship in blacks or whether aerobic fitness influences weight gain in white or black children.Methods. One hundred fifteen children, 72 white (55 girls and 17 boys) and 43 black (24 girls and 19 boys) were recruited for this study. Aerobic fitness, resting, total, and activity-related energy expenditure and body composition were measured at baseline. The children returned annually for 3 to 5 repeated measures of body composition. The influence of the initial measures of energy expenditure and fitness on the subsequent rate of increase in adiposity was examined, adjusting for initial body composition, age, ethnicity, gender, and Tanner stage. Because 20 children did not attain maximum oxygen consumption, the sample size for the combined analysis was 95.Results. Initial fat mass was the main predictor of increasing adiposity in this cohort of children, with greater initial fat predicting a higher rate of increase of adiposity. There was also a significant negative relationship between aerobic fitness and the rate of increasing adiposity (F 1,82 ‫؍‬ 3.92). With every increase of .1 L/minute of fitness, there was a decrease of .081 kg fat per kg of lean mass gained. None of the measures of energy expenditure significantly predicted increasing adiposity in white or black children.Conclusions. Initial fat mass was the dominant factor influencing increasing adiposity; however, aerobic fitness was also a significant independent predictor of increasing adiposity in this cohort of children. Resting, total, or activity-related energy expenditure did not predict increasing adiposity. It seems that aerobic fitness may be more important than absolute energy expenditure in the development of obesity in white or black children. Pediatrics 2000;106(4). URL: http://www. pediatrics.org/cgi/content/full/106/4/e50; energy expenditure, fitness, longitudinal, obesity.

Cardiorespiratory fitness is positively associated with a healthy dietary pattern in New Zealand adolescents

“…Although testing was completed throughout the school day, the maximal nature of the testing means that there is unlikely to be any effect from circadian variation in VO 2 uptake kinetics (40) . Physical activity levels may influence aerobic fitness; however, it has been shown that aerobic fitness is independently associated with adiposity in children (32) and therefore the aim of the present study was to investigate fitness rather than physical activity.…”

Does physical activity equally predict gain in fat mass among obese and nonobese young adults?

“…25 Thus, the behavioural component of activity may not be captured when PAEE is measured by the DLW method, which may then explain the nonsignificant prospective associations previously observed between activity energy expenditure and gain in FM. [15][16][17][18][19] The impact of exercise intensity on change in body composition is equivocal. [20][21][22][23] Our results suggest that change in overall activity, but not change in any of the subcomponents of activity, is inversely associated with change in FM.…”

“…Most studies incorporating an objective measure of PA have been unable to demonstrate a prospective association between PA or PAEE and change in BW or FM. [15][16][17][18][19] One recent study has suggested a prospective association between PA and change in FM but this association was modified by age. 20 Furthermore, the potential impact of exercise intensity on change in BW and FM remains elusive, [21][22][23][24] and it is not known which if any of the subcomponents of free-living PA contributes more to change in BW and FM.…”

Cardiorespiratory fitness and body mass index of 9–11-year-old English children: a serial cross-sectional study from 1998 to 2004

“…As low fitness is associated with high fatness [7][8][9][10] and low physical activity, 11 the increasing prevalence of obesity and of the proportion of children leading sedentary lifestyles suggest that overall fitness levels may have fallen. Hence, as fitness is an important component of metabolic health [12][13][14][15][16] and a strong independent predictor of premature death, 17 identifying changes in fitness levels among children during the 'obesity epidemic' could indicate the need for interventions to improve fitness in this age group.…”