THE ENERGY REQUIREMENTS IN INDIVIDUALS WITH MENTAL RETARDATION

为了研究智力低下(MRS)患者的能量代谢特征，我们对23名男性MRS和相同数量的男性志愿者进行了不同体力活动水平(30、50和70m/min)的能量消耗、最大耗氧量(Vo_2max)和身体成分的测定。这两组人在年龄、身高和体重方面都是单独匹配的。能源成本是通过道格拉斯袋子技术衡量的。采用新近发展的六氟化硫(SF6)稀释技术测量人体成分，用三维加速度计评估人体运动，并测量血浆中的常量营养素指数。结果：坐姿、站姿和步行速度分别为30m/min和50m/min时，MRS的能量消耗显著高于对照组(p&lt；0.05)，而基础代谢率和静息代谢率两组相似。MRS组VO_2max显著低于对照组(P<0.05)。加速法显示MRS患者运动过度，这可能解释了他们运动时能量消耗较高的原因。相比之下，在体脂百分比和瘦体重方面没有观察到显著差异。MRS患者血浆总胆固醇、三酰甘油和白蛋白浓度显著低于对照组，提示MRS患者的能量代谢负荷不如非MRS患者。他们日常生活中有限的体力活动可能是原因。MRS的这些能量代谢特点应该被考虑到计划他们适当的饮食计划和体力活动计划

To characterize energy metabolism in individuals with mental retardation (MRs), We meaured energy cost at several physical activity levels (basal, supine, siffting, standing, and walking at 30,50 and 70 m/min), maximal oxygen consumption (Vo_2max), and body composition in 23 male MRs and the same number of volunteer male controls. Both groups were individually matched for age, body height, and body weight. Energy costs were measured by the Douglas bag technique. The recently developed sulfur hexafluoride (SF_6) dilution technique was employed for measuring body composition.In addition, 3-dimensional accelerometry was used for evaluating body movements, and plasma indices of macronutrients were also measured. Results : The energy cost of MRs, when sitting, standing, and walking at 30 and 50 m/min, was significantly higher than that of controls (p<0.05), while the basal and resting metabolic rates were similar in both groups. Vo_2max was significantly lower (P<0.05) in MRs than controls. Accelerometry demonstrated excessive movements in MRs, which may explain their higher energy cost of exercise. By contrast, no significant difference was observed in percent body fat and lean body mass. Concentrations of plasma total cholesterol, triacylglycerols and albumin were significantly lower in MRs compared with controls.Our findings suggest that MRs are burdened with energy metabolism less economical than non-MRs. A limited physical activity in their daily life may be the cause. These characteristics of MRs' energy metabolism should be considered for planning their proper dietary schdules and physical activity programs