Effects of exercise intensity on cardiovascular fitness, total body composition, and visceral adiposity of obese adolescents.

BACKGROUND Little is known about how the intensity of exercise influences cardiovascular fitness and body composition, especially in obese adolescents. OBJECTIVE Our goal was to determine the effects of physical training intensity on the cardiovascular fitness, percentage of body fat (%BF), and visceral adipose tissue (VAT) of obese adolescents. DESIGN Obese 13-16-y-olds (n = 80) were assigned to 1) biweekly lifestyle education (LSE), 2) LSE + moderate-intensity physical training, or 3) LSE + high-intensity physical training. The intervention lasted 8 mo. Physical training was offered 5 d/wk, and the target energy expenditure for all subjects in physical training groups was 1047 kJ (250 kcal)/session. Cardiovascular fitness was measured with a multistage treadmill test, %BF with dual-energy X-ray absorptiometry, and VAT with magnetic resonance imaging. RESULTS The increase in cardiovascular fitness in the high-intensity physical training group, but not in the moderate-intensity group, was significantly greater than that in the LSE alone group (P = 0.009); no other comparisons of the 3 groups were significant. Compared with the LSE alone group, a group composed of subjects in both physical training groups combined who attended training sessions >or=2 d/wk showed favorable changes in cardiovascular fitness (P < 0.001), %BF (P = 0.001), and VAT (P = 0.029). We found no evidence that the high-intensity physical training was more effective than the moderate-intensity physical training in enhancing body composition. CONCLUSIONS The cardiovascular fitness of obese adolescents was significantly improved by physical training, especially high-intensity physical training. The physical training also reduced both visceral and total-body adiposity, but there was no clear effect of the intensity of physical training.

[1]  C. Bouchard,et al.  Effect of intensity of physical activity on body fatness and fat distribution. , 1990, The American journal of clinical nutrition.

[2]  C. Bouchard,et al.  Impact of exercise intensity on body fatness and skeletal muscle metabolism. , 1994, Metabolism: clinical and experimental.

[3]  M. Litaker,et al.  Correlates of individual differences in body-composition changes resulting from physical training in obese children. , 1999, The American journal of clinical nutrition.

[4]  M Litaker,et al.  Body-composition measurement in 9-11-y-old children by dual-energy X-ray absorptiometry, skinfold-thickness measurements, and bioimpedance analysis. , 1996, The American journal of clinical nutrition.

[5]  M. Litaker,et al.  Visceral adipose tissue and markers of the insulin resistance syndrome in obese black and white teenagers. , 2000, Obesity research.

[6]  B. Gutin,et al.  Physical training improves body composition of black obese 7- to 11-year-old girls. , 1995, Obesity research.

[7]  C. Christiansen,et al.  Accuracy of measurements of body composition by dual-energy x-ray absorptiometry in vivo. , 1993, The American journal of clinical nutrition.

[8]  M. Litaker,et al.  Prediction of visceral adipose tissue from simple anthropometric measurements in youths with obesity. , 1999, Obesity research.

[9]  D. Fields,et al.  Aerobic Fitness, Not Energy Expenditure, Influences Subsequent Increase in Adiposity in Black and White Children , 2000, Pediatrics.

[10]  G. Hunter,et al.  Effects of strength training on intra-abdominal adipose tissue in obese prepubertal girls. , 1998, Medicine and science in sports and exercise.

[11]  I M Buzzard,et al.  Sources of data for developing and maintaining a nutrient database. , 1988, Journal of the American Dietetic Association.

[12]  D. Massicotte,et al.  Cardiorespiratory adaptations to training at specified intensities in children. , 1974, Medicine and science in sports.

[13]  J. Sallis,et al.  Seven-day recall and other physical activity self-reports in children and adolescents. , 1993, Medicine and science in sports and exercise.

[14]  K. Berg,et al.  Exercise training effects on serum lipids of prepubescent boys and adult men. , 1986, Medicine and science in sports and exercise.

[15]  B. Gutin,et al.  Visceral adipose tissue and cardiovascular risk factors in obese children. , 1998, The Journal of pediatrics.

[16]  M. Litaker,et al.  Effect of physical training on total and visceral fat in obese children. , 1999, Medicine and science in sports and exercise.

[17]  W. Dietz,et al.  Reference data for obesity: 85th and 95th percentiles of body mass index (wt/ht2)—a correction , 1991 .

[18]  M. Goran,et al.  Issues relating to normalization of body fat content in men and women. , 1995, International journal of obesity and related metabolic disorders : journal of the International Association for the Study of Obesity.

[19]  Cedric X. Bryant,et al.  ACSM's guidelines for exercise testing and prescription , 1995 .

[20]  W. Tamborlane,et al.  Fat distribution and cardiovascular risk factors in obese adolescent girls: importance of the intraabdominal fat depot. , 1996, The American journal of clinical nutrition.

[21]  R Guardo,et al.  Quantification of adipose tissue by MRI: relationship with anthropometric variables. , 1992, Journal of applied physiology.

[22]  B. Gutin,et al.  Description and process evaluation of a physical training program for obese children. , 1999, Research quarterly for exercise and sport.

[23]  M. Stachura,et al.  Relation of percentage of body fat and maximal aerobic capacity to risk factors for atherosclerosis and diabetes in black and white seven- to eleven-year-old children. , 1994, The Journal of pediatrics.

[24]  M. Litaker,et al.  Effect of physical training and its cessation on percent fat and bone density of children with obesity. , 1999, Obesity research.

[25]  T. Rowland.  The Case of the Elusive Denominator , 1998 .