A comparison of the effects of a single bout of aerobic and strength training exercise on the insulin response to glucose ingestion in sedentary, non-diabetic women
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The purpose of this study was to examine insulin responses following a single session of aerobic or strength training exercise in 27 sedentary (V02max = 33 ± 5 ml/kg/min), normoglycemic women (26 ± 8 yrs, 65 ± 15 kg). A single session of either an aerobic or strength training exercise can significantly reduce the insulin response to glucose in untrained persons. However, insulin responses following a single session of aerobic and strength training exercise have yet to be compared in the same person. Three treatments were completed: rest, aerobic exercise (treadmill walking at 70% V02max for 50 min), and strength exercise (11 exercises, 3 sets, 10 reps at 40, 55, and 75% of lRM). Each treatment was conducted 1 to 4 weeks apart and within 5 to 12 days after the onset of menstruation. A 75-gram oral glucose tolerance test was administered 15 hours after exercise and 12 hours postprandial. Blood samples drawn at O (fasting), 15, 30, 60, 90, 120, and 150 minutes after glucose ingestion were analyzed for glucose, insulin, and C-peptide. Compared to rest (4.75 ± 0.27 mM), there was a significant decrease (n<.05) in fasting glucose following the strength (4.55 ± 0.35 mM), but not the aerobic exercise ( 4.64 ± 0.34 mM). Postexercise concentrations of fasting insulin and C-peptide were unchanged compared to rest. Glucose, insulin, and C-peptide responses, expressed as area under the curve, were not statistically different from rest. Rest Glucose area (mM) 912.6 ± 28.5 Insulin area (pM x 104 ) 6.3 ± 0.4 C-Peptide area (pM x 104 ) 32.4 ± 1.6 Aerobic 895.2 ± 30.8 6.4 ± 0.5 32.9 ± 1.7 Strength 861.5 ± 28.3 6.2±0.6 33.6 ± 2.4 Fasting plasma free fatty acid, fasting sex hormone binding globulin, and dietary intake were equivalent following each treatment, while fasting CK was significantly elevated following both the aerobic and strength exercise compared to rest. None of the anthropometric, body composition, fitness, or fasting plasma variables that could potentially influence glucoregulation significantly predicted the change in insulin response area between rest and either exercise. Thus in sedentary, premenopausal women, neither a single session of aerobic nor strength exercise significantly decreases the insulin response area to an oral glucose challenge.