Amati Francesca, Dubé John J, Stefanovic-Racic Maja, Toledo Frederico G, Goodpaster Bret H
Department of Health and Physical Activity, School of Education, University of Pittsburgh, PA 15213, USA.
Med Sci Sports Exerc. 2009 Feb;41(2):265-9. doi: 10.1249/MSS.0b013e318187c010.
Exercise- and weight loss-induced improvements in insulin resistance (IR) are variable; some individuals experience robust enhancements in insulin sensitivity, whereas others do not. Thyroid hormone status is related to IR, but it is not clear whether subclinical hypothyroidism may help to explain the variability in improvements in IR with diet and exercise. The purpose of this study was to examine whether thyroid hormone status is related to the improvement in insulin sensitivity and physical fitness after weight loss and exercise training.
By retrospective nested case-control analysis, eight subclinical hypothyroid (sHT) subjects and eight matched euthyroid controls underwent a euglycemic hyperinsulinemic clamp and peak oxygen uptake test, before and after a 16-wk program of moderate aerobic exercise combined with diet-induced weight loss. All subjects were middle-aged (57.3 +/- 3.3 yr), were overweight to obese (body mass index = 33.1 +/- 0.8 kg m(-2)), and had impaired glucose tolerance.
The improvement in insulin sensitivity was significantly lower (P < 0.05) in the sHT group than in the euthyroid group. Both groups performed similar amounts of regular exercise and lost a significant amount of body weight during the intervention. VO(2peak) tended to improve in the euthyroid group but not in the sHT group.
Subclinical hypothyroidism may interfere with beneficial adaptations on muscle metabolism and physical fitness that typically occur with weight loss and increased physical activity. These results may have significant clinical implications because of the high prevalence of both hypothyroidism and insulin resistance in the aging population.
运动和减肥引起的胰岛素抵抗（IR）改善情况存在差异；一些人胰岛素敏感性显著增强，而另一些人则不然。甲状腺激素状态与IR有关，但尚不清楚亚临床甲状腺功能减退是否有助于解释饮食和运动导致的IR改善差异。本研究的目的是探讨甲状腺激素状态与减肥及运动训练后胰岛素敏感性和体能改善之间的关系。
通过回顾性巢式病例对照分析，8名亚临床甲状腺功能减退（sHT）受试者和8名匹配的甲状腺功能正常对照者在进行为期16周的中等强度有氧运动结合饮食诱导减肥计划前后，接受了正常血糖高胰岛素钳夹试验和峰值摄氧量测试。所有受试者均为中年（57.3±3.3岁），超重至肥胖（体重指数=33.1±0.8kg m-2），且糖耐量受损。
sHT组胰岛素敏感性的改善显著低于甲状腺功能正常组（P<0.05）。两组在干预期间进行的常规运动量相似，体重均显著减轻。甲状腺功能正常组的VO2峰值有改善趋势，而sHT组则无。
亚临床甲状腺功能减退可能会干扰通常伴随体重减轻和体力活动增加而出现的对肌肉代谢和体能的有益适应性变化。由于老年人群中甲状腺功能减退和胰岛素抵抗的高患病率，这些结果可能具有重要的临床意义。
