PURPOSE:The predicted value of maximal exercise capacity (MVO2) during a cardiopulmonary exercise test (CPET) is based on weight, height, age and gender. However, total body weight (TBW) includes fat and non fat body mass. We hypothesized that the predictive value of MVO2 would be more precise if the oxygen uptake was estimated using fat free mass (FFM) instead of TBW.
METHODS:We studied 42 males and 39 females. Body weight (Wt) was measured in Kg and BMI calculated. Body composition analysis (fat and lean weight, total body water) was assessed using the Bodystat 1500 and we calculated FFM index; lean weight/height2 (Kg/m2). Exercise testing (CPET) was performed on a cycle ergometer while breathing room air. Linear regression equations were built for MVO2 (L) using total weight (Kg) and FFM (Kg).
RESULTS:Patients had a mean age of 55 (15) years, height 167 (9) cm, weight 76 (17) kg and FEV1 % predicted 97% (11). Body mass analysis showed a FFM of 53 (13) Kg and a FFM index of 19 (3) Kg/m2. A significantly stronger correlation with tighter 95% CI was seen between MVO2 (L·min-1) and FFM (r= 0.71, p<0.0001) than between MVO2 (L·min-1) and absolute weight (r =0.41, p=0.0001).
CONCLUSION:Our results indicate that the use of FFM rather than absolute weight is a more physiologic method to estimate the maximal exercise capacity.
CLINICAL IMPLICATIONS:The use of FFM in place of absolute weight may improve the predictive accuracy of the exercise capacity measurement especially in people with different body compositions.
DISCLOSURE:Sohail Qadir, None.