title: Effects of body composition on insulin sensitivity.
abstract: We studied the effects of body composition and maximal aerobic power on insulin sensitivity in 23 normal-weight, healthy male subjects. Eight were weight lifters, eight were long-distance runners, and seven were untrained controls. In each subject, the percentage of body weight (BW) made up of muscle and fat tissue (% muscle and % fat, respectively), the maximal aerobic power (VO2max), and the tissue sensitivity to insulin were measured. The weight lifters were characterized by 35% higher % muscle as compared with the runners or controls (P less than 0.01). VO2max in the runners was 30-40% higher than in the weight lifters or controls (P less than 0.001). During the euglycemic clamp studies, similar steady-state plasma glucose and insulin levels were achieved in each group. When calculated per total BW, the rate of glucose metabolism (M) was virtually identical in the weight lifters (10.26 +/- 1.02 mg/kg BW/min) and the runners (10.03 +/- 0.86 mg/kg BW/min), and 4045% higher than in the controls (7.10 +/- 0.75 mg/kg BW/min, P less than 0.05). When calculated per muscle mass (Mm), only the runners had a higher than normal rate of glucose metabolism (P less than 0.02). M was directly proportional to% muscle (r = 0.54, P less than 0.01) and inversely related to % fat (r = -0.72, P less than 0.001). The multiple linear regression analysis revealed a highly significant multivariate correlation between M and the combined effect of % muscle, %fat, and VO2max (r = 0.78, P less than 0.0005).(ABSTRACT TRUNCATED AT 250 WORDS)
mesh_terms: D000273:Adipose Tissue / Q000033:anatomy & histology; D000328:Adult; D001823:Body Composition; D001835:Body Weight; D005947:Glucose / Q000378:metabolism; D006801:Humans; D007328:Insulin / Q000494:pharmacology*; D008297:Male; D009132:Muscles / Q000033:anatomy & histology; D010101:Oxygen Consumption; D012420:Running; D014891:Weight Lifting
chemical_list: D007328:Insulin; D005947:Glucose