Extremely obese patients: improvements in exercise tolerance with physical training and weight loss.

The relationship between improvements in exercise tolerance and body weight was determined for 11 extremely obese patients (mean entry weight = 189kg) concomitantly participating in progressive physical training (walking-jogging) and severe caloric restriction (600kcal/day) to induce weight loss as part of a residential multidisciplinary rehabilitation program. Two standardized tests (treadmill mile-walk and graded-exhaustive) to quantitatively evaluate exercise performance were administered periodically. Significant weight reductions and improvements in exercise tolerance were observed, with measures of the latter occurring relatively sooner. Correlation coefficients between body weight and performance or physiologic response measures were extremely low, indicating widespread individual responsiveness to training and the probable separateness of training and dietary effects. A moderate inverse correlation was found between body weight and a simple measure of work performance: endurance time to volitional exhaustion (r = -0.45). Training programs of moderate rather than higher intensity, duration, and progression rate were used with this obese group. Such programs can be safely administered and will be well tolerated but therapists should recognize the inability to predict improvements in exercise performance on the basis of the current body weights of individual patients. The major application of results from standardized exercise tests, therefore, resides in direct reinforcement of patient progress.