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A 12‐Week Aerobic Exercise Program Reduces Hepatic Fat Accumulation and Insulin Resistance in Obese, Hispanic Adolescents
Author(s) -
Heijden GertJan,
Wang Zhiyue J.,
Chu Zili D.,
Sauer Pieter J.J.,
Haymond Morey W.,
Rodriguez Luisa M.,
Sunehag Agneta L.
Publication year - 2010
Publication title -
obesity
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.438
H-Index - 199
eISSN - 1930-739X
pISSN - 1930-7381
DOI - 10.1038/oby.2009.274
Subject(s) - insulin resistance , medicine , endocrinology , aerobic exercise , obesity , insulin , vo2 max , blood pressure , heart rate
The rise in obesity‐related morbidity in children and adolescents requires urgent prevention and treatment strategies. Currently, only limited data are available on the effects of exercise programs on insulin resistance, and visceral, hepatic, and intramyocellular fat accumulation. We hypothesized that a 12‐week controlled aerobic exercise program without weight loss reduces visceral, hepatic, and intramyocellular fat content and decreases insulin resistance in sedentary Hispanic adolescents. Twenty‐nine postpubertal (Tanner stage IV and V), Hispanic adolescents, 15 obese (7 boys, 8 girls; 15.6 ± 0.4 years; 33.7 ± 1.1 kg/m 2 ; 38.3 ± 1.5% body fat) and 14 lean (10 boys, 4 girls; 15.1 ± 0.3 years; 20.6 ± 0.8 kg/m 2 ; 18.9 ± 1.5% body fat), completed a 12‐week aerobic exercise program (4 × 30 min/week at ≥70% of peak oxygen consumption (VO 2 peak)). Measurements of cardiovascular fitness, visceral, hepatic, and intramyocellular fat content (magnetic resonance imaging (MRI)/magnetic resonance spectroscopy (MRS)), and insulin resistance were obtained at baseline and postexercise. In both groups, fitness increased (obese: 13 ± 2%, lean: 16 ± 4%; both P < 0.01). In obese participants, intramyocellular fat remained unchanged, whereas hepatic fat content decreased from 8.9 ± 3.2 to 5.6 ± 1.8%; P < 0.05 and visceral fat content from 54.7 ± 6.0 to 49.6 ± 5.5 cm 2 ; P < 0.05. Insulin resistance decreased indicated by decreased fasting insulin (21.8 ± 2.7 to 18.2 ± 2.4 µU/ml; P < 0.01) and homeostasis model assessment of insulin resistance (HOMA IR ) (4.9 ± 0.7 to 4.1 ± 0.6; P < 0.01). The decrease in visceral fat correlated with the decrease in fasting insulin ( R 2 = 0.40; P < 0.05). No significant changes were observed in any parameter in lean participants except a small increase in lean body mass (LBM). Thus, a controlled aerobic exercise program, without weight loss, reduced hepatic and visceral fat accumulation, and decreased insulin resistance in obese adolescents.