A new equation to predict peak VO 2 in obese patients during cardiopulmonary exercise testing

Summary We aimed to develop an equation to predict peak VO 2 in obese subjects undergoing CPET . In addition, we evaluated and compared three published equations. We randomized 346 obese subjects undergoing CPET into a group for developing the equation ( n  = 272) and a group for cross‐validation ( n  = 74), compared through the Bland and Altman method. Height, sex and age were responsible for 85·5% of total variability of the peak VO 2. Additional 1% and 0·7% of the variability were, respectively, explained by physical inactivity and diabetes. The equation devised was as follows:peakVO 2mlmin − 1= − 677· 8+ ( 2135 · 9× height m ) + ( 706 · 8×sex males = 1 ; females = 0 )− ( 15 · 5× age years ) − ( 161·1 × physicalinactivity yes = 1 ; no = 0 )− ( 176 · 3 × diabetes yes = 1 ; no = 0 ) .The mean difference between the estimated and measured peak VO 2 was 7 ml min −1 , with a 23·9% bias. Published equations overestimated the peak VO 2 by 35·3%, 49·1% and 46·2% bias. The equation developed in this study performed better in predicting peak VO 2 in obese adults improving ramp protocol design and CRF evaluations in obese subjects.