Purpose: This study compared the accuracy of common clinical treadmill and arm ergometry equations in estimating the rate of oxygen consumption for males with coronary artery disease.
Methods: Measured and estimated submaximal and maximal oxygen consumption (VO2sub and VO2max) were compared during clinical treadmill (TM) and arm ergometry (AE) graded exercise tests in 15 males with established coronary artery disease (CAD). Estimated VO2sub and VO2max were derived from popular modality specific estimation equations, including those of the American College of Sports Medicine, Bruce and colleagues, Balady and colleagues, and Manfre and colleagues.
Results: The American College of Sports Medicine (ACSM) 1991 TM equation overestimated VO2sub from 0.3 +/- 0.6 to 1 +/- 0.7 metabolic equivalents (METS) and VO2max by 3 +/- 3 METS, whereas the Bruce Normal Submax and Bruce Cardiac Submax equations inaccurately estimated VO2sub from -1 +/- 0.6 to 0.9 +/- 0.7 METS. The Bruce Active Max and Bruce Sedentary Max equations overestimated VO2max from 1 +/- 2 to 2 +/- 2 METS, whereas the Bruce Cardiac Max equation accurately estimated oxygen consumption at maximal exercise. The ACSM and Manfre Healthy AE equations underestimated VO2sub at low and intermediate workloads from 0.4 +/- 0.4 to 0.8 +/- 0.4 METS. However, the Balady Male and Manfre Cardiac AE equations underestimated VO2 at each submaximal work load from 0.6 +/- 0.3 to 1 +/- 0.6 METS and at maximal work loads from 0.8 +/- 0.9 to 2 +/- 0.8 METS. The ACSM and Manfre Healthy AE equations accurately estimated VO2 at greater submaximal work loads and at maximal exercise.
Conclusions: These data suggest that the ability to estimate VO2 in males with CAD is more accurately performed during nonweight-bearing arm activity, although the reason is not entirely understood, and significant inconsistencies exist in the ability to accurately estimate VO2 during treadmill exercise. These data further suggest concern regarding exercise prescription from estimated values derived from both treadmill and arm ergometry tests, because submaximal, and in some instances maximal, estimations were inaccurate. Future research should focus on the development of accurate estimations for those with CAD, primarily during submaximal work.