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.