Correlation between Body Composition and Walking Capacity in Severe Obesity

Background
Obesity is associated with mobility reduction due to mechanical factors and excessive body fat. The six-minute walk test (6MWT) has been used to assess functional capacity in severe obesity.
Objective
To determine the association of BMI, total and segmental body composition with distance walked (6MWD) during the six-minute walk test (6MWT) according to gender and obesity grade.
Setting
University of São Paulo Medical School, Brazil; Public Practice.
Methods
Functional capacity was assessed by 6MWD and body composition (%) by bioelectrical impedance analysis in 90 patients.
Results
The mean 6MWD was 514.9 ± 50.3 m for both genders. The male group (M: 545.2 ± 46.9 m) showed a 6MWD higher (p = 0.002) than the female group (F: 505.6 ± 47.9 m). The morbid obese group (MO: 524.7 ± 44.0 m) also showed a 6MWD higher (p = 0.014) than the super obese group (SO: 494.2 ± 57.0 m). There was a positive relationship between 6MWD and fat free mass (FFM), FFM of upper limps (FFM_UL), trunk (FFM_TR) and lower limbs (FFM_LL). Female group presented a positive relationship between 6MWD and FFM, FFM_UL and FFM_LL and male group presented a positive relationship between 6MWD and FFM_TR. In morbid obese group there was a positive relationship between 6MWD with FFM, FFM_UL, FFM_TR and FFM_LL. The super obese group presented a positive relationship between 6MWD with FFM, FFM_TR and FFM_LL.
Conclusions
Total and segmental FFM is associated with a better walking capacity than BMI.

背景
肥胖可因机械负荷因素与体脂过多导致运动能力下降。六分钟步行试验（six-minute walk test, 6MWT）已被用于评估重度肥胖患者的运动功能容量。

研究目的
本研究旨在明确按性别与肥胖分级分层后，身体质量指数（Body Mass Index, BMI）、总体及节段体成分与六分钟步行试验中的步行距离（six-minute walk distance, 6MWD）的相关性。

研究场景
巴西圣保罗大学医学院；公共医疗实践场景。

研究方法
纳入90例患者，采用六分钟步行距离（6MWD）评估其运动功能容量，通过生物电阻抗分析法检测体成分百分比。

研究结果
全体受试者的六分钟步行距离（6MWD）均值为514.9±50.3米。男性组（545.2±46.9米）的6MWD显著高于女性组（505.6±47.9米，p=0.002）。病态肥胖组（MO：524.7±44.0米）的6MWD同样高于超肥胖组（SO：494.2±57.0米，p=0.014）。6MWD与无脂体质（fat free mass, FFM）、上肢无脂体质（FFM_UL）、躯干无脂体质（FFM_TR）及下肢无脂体质（FFM_LL）呈正相关。女性组的6MWD与FFM、FFM_UL及FFM_LL呈正相关，而男性组的6MWD仅与FFM_TR呈正相关。病态肥胖组的6MWD与FFM、FFM_UL、FFM_TR及FFM_LL均呈正相关。超肥胖组的6MWD与FFM、FFM_TR及FFM_LL呈正相关。

结论
总体及节段无脂体质与步行能力的相关性优于身体质量指数（BMI）。