Peak oxygen uptake prediction from a moderate perceptually-regulated 1-km treadmill walk in male cardiac patients.

Objective: To determine whether a moderate one-km treadmill walk (1KTWT) could be used to predict peak oxygen uptake (VO2peak) in patients with cardiovascular disease (CVD). Setting: Outpatient cardiac rehabilitation. Methods: 178 male patients, aged 38 to 83 yrs, completed a VO2peak treadmill test and a 1KTWT using a self-regulated intensity of 11-13/20 on the Borg scale. Multivariable regression analysis was used to develop equations for predicting VO2peak in a development group (DEV, n=110), both for subjects prescribed and not prescribed a β-blocking agent (BB/NBB, 66/44). These equations were then applied to a cross-validation and reproducibility group (CVR, n=68, BB/NBB, 37/31), who completed the protocol twice within two weeks. Results: Analysis from 1KTWT in the DEV group showed that age, body mass index, walking speed and heart rate were the most potent predictors of VO2peak. Measured and predicted VO2peak were not significantly different, and were strongly associated among both the NBB (r=0.81, P<0.0001) and BB (r=0.69, P<0.0001) groups, with a mean residual of ~1.0 ml/kg/min. When applied to the CVR group, the equations similarly yielded strong associations (r=0.64, P<0.001 and r=0.71, P