Ferrara Cynthia M, Goldberg Andrew P, Ortmeyer Heidi K, Ryan Alice S
Division of Gerontology, University of Maryland, Baltimore, and Baltimore Department of Veterans Affairs Medical Center, Geriatric Research, Education, and Clinical Center (GRECC), USA.
J Gerontol A Biol Sci Med Sci. 2006 May;61(5):480-7. doi: 10.1093/gerona/61.5.480.
Aging is associated with insulin resistance, primarily as a result of physical inactivity and increased abdominal obesity. We hypothesized that aerobic (AEX) or resistive (RT) exercise training would result in comparable improvements in glucose disposal in older men, but that there would be different metabolic adaptations in skeletal muscle.
Thirty-nine older (63+/-1 years, mean+/-standard error of the mean), overweight and obese (body mass index=30.3+/-0.4 kg/m2) men were assigned to AEX (treadmill walking and/or jogging, n=19) or RT (upper and lower body, n=20) programs 3 d/wk for 6 months, with 9 completing AEX and 13 completing RT. Testing before and after the exercise programs included body composition, euglycemic-hyperinsulinemic clamps, and vastus lateralis muscle biopsies.
Maximal oxygen consumption (VO2max) increased by 16% after AEX (p<.01), while leg and arm muscle strength increased by 45+/-5% and 27+/-5% after RT (p<.0001). Although participants were monitored to maintain their body weight during the exercise program, body weight decreased by 2% after AEX (p<.05), and increased by 2% after RT (p<.05). Whole-body glucose disposal, determined during the last 30 minutes of a 2-hour 480 pmol/m2/min euglycemic-hyperinsulinemic clamp, increased comparably by 20%-25% after AEX (51+/-5 to 61+/-5 microM/kgfat-free mass/min, p<.05) and RT (49+/-3 to 58+/-3 microM/kgfat-free mass/min, p<.05). The increase in vastus lateralis muscle glycogen synthase fractional activity in response to insulin stimulation was significantly higher after AEX compared to after RT (279+/-59% compared to 100+/-28% change, p<.05). Neither AEX nor RT altered muscle glycogen synthase total activity, glycogen content, or levels of phosphotidylinositol 3-kinase.
These results suggest that AEX and RT result in comparable improvements in glucose metabolism in older men, whereas an increase in insulin activation of glycogen synthase occurred only with AEX. These improvements in insulin sensitivity could reduce the risk of metabolic syndrome and type 2 diabetes and attenuate the development of cardiovascular disease.
衰老与胰岛素抵抗相关，主要是由于缺乏身体活动和腹部肥胖增加。我们假设有氧运动（AEX）或抗阻训练（RT）会使老年男性的葡萄糖代谢得到类似改善，但骨骼肌会有不同的代谢适应性变化。
39名年龄较大（63±1岁，均值±均值标准误）、超重和肥胖（体重指数 = 30.3±0.4 kg/m²）的男性被分配到AEX组（跑步机行走和/或慢跑，n = 19）或RT组（上下肢训练，n = 20），每周训练3天，共6个月，其中9人完成AEX训练，13人完成RT训练。运动计划前后的测试包括身体成分、正常血糖 - 高胰岛素钳夹试验以及股外侧肌活检。
AEX后最大摄氧量（VO2max）增加了16%（p <.01），而RT后腿部和手臂肌肉力量分别增加了45±5%和27±5%（p <.0001）。尽管在运动计划期间对参与者进行监测以维持体重，但AEX后体重下降了2%（p <.05），RT后体重增加了2%（p <.05）。在2小时480 pmol/m²/min正常血糖 - 高胰岛素钳夹试验的最后30分钟测定的全身葡萄糖代谢，AEX后（51±5至61±5 μmol/kg去脂体重/分钟，p <.05）和RT后（49±3至58±3 μmol/kg去脂体重/分钟，p <.05）均有类似的20% - 25%的增加。与RT后相比，AEX后股外侧肌糖原合酶对胰岛素刺激的反应性分数活性增加显著更高（变化分别为279±59%和100±28%，p <.05）。AEX和RT均未改变肌肉糖原合酶的总活性、糖原含量或磷脂酰肌醇3激酶水平。
这些结果表明AEX和RT在老年男性的葡萄糖代谢方面带来类似的改善，而糖原合酶的胰岛素激活增加仅发生在AEX后。胰岛素敏感性的这些改善可降低代谢综合征和2型糖尿病的风险，并减轻心血管疾病的发展。
