Adipokine Responses to Exercise Repeated on Successive Days in Men with Metabolic Syndrome
Type of Degreedissertation
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Leptin and adiponectin are two insulin-sensitizing adipokines that may be influenced transiently by exercise and contribute to the post-exercise improvement in insulin-mediated glucose uptake. The influence of exercise on these adipokines is inconsistent and confounded by a variety of factors. Therefore, the purpose of this study was to characterize the temporal responses of adipokines to repeated exercise bouts in successive days in obese males with metabolic syndrome and their relationship with markers of insulin resistance. Exercise sessions were completed by expending 350 kcals of energy, walking on a treadmill at 60 to 70% of V.O2 max, on each of four successive days. Blood samples from eleven middle-aged men (Age: 50 8.0 years, BMI = 32.0 4.6 kg/m2, % Fat = 29 4.0 (% of body weight), VO2max = 28.9 4.3 ml.kg.-1min-1, SBP = 140 ± 8.6 mmHg, DBP = 92 ± 6.3 mmHg, triglyceride = 267 ± 145.0 mg/dL, HDL-C = 32 ± 5.0 mg/dL, glucose = 99.6 ± 12.8 mg/dL) were obtained before each exercise session and obtained again at 24 and 72 hours after the last exercise bout. Changes in plasma volume-adjusted total and HMW adiponectin, leptin, NEFA, glucose and insulin were determined using multiple 1 x 6 repeated-measures ANOVAs. Insulin concentrations decreased 26% with a single bout of exercise. Leptin decreased 9% after two exercise sessions and remained lower up to 24 hours following the last exercise session. NEFA, glucose, the HOMA score, adiponectin and HMW adiponectin remained unaltered with exercise. The accumulated effect of multiple bouts of exercise in leptin concentrations was greater than the effect obtained from two exercise bouts but not related to changes in insulin concentrations or the HOMA score. Leptin changes following exercise may contribute to lower insulin resistance following exercise but is not necessary for the reduced insulin resistance observed after exercise.