Time-Course Increases in Cardiorespiratory Fitness after Bariatric Surgery

Abstract

BACKGROUND: The rise in morbid obesity has led to advancements in clinical treatment modalities. Of these, bariatric surgery (BS) has been shown to elicit significant weight loss in the morbidly obese. Few data, however, are available regarding the effect of BS on cardiorespiratory (CR) fitness parameters in this escalating patient subset. PURPOSE: To determine the effect of BS on CR fitness, we evaluated CR fitness following BS in a morbidly obese population. METHODS: Fourteen patients (12 women, 2 men; mean + SD age = 46 + 11 years) who underwent Roux-en-Y gastric bypass surgery were studied. As part of their pre- and post-surgical screening, maximal graded exercise testing with concomitant oxygen consumption (VO2) measurement was conducted. Pre- and post-BS tests were compared to determine changes in CR fitness. RESULTS: Select demographic and CR variables pre- and post-surgery are shown in the Table. Significant decreases in body weight and BMI and increases in treadmill time and maximal VO, expressed as mL/kg/min or metabolic equivalents (METs), were noted following BS [mean follow-up time = 139 days (range = 32–396 days)]. The CR benefits of BS appeared to be time-dependent; patients having follow-up testing > 100 days (mean ± SD = 221 ± 109.4) post-surgery demonstrated significantly greater decreases in body weight and increases in CR fitness as compared with those who had earlier (mean ± SD = 57 ± 16.9 days) follow-up.Table: Changes in body composition and cardiorespiratory variables following bariatric surgeryCONCLUSION: Bariatric surgery results in a marked weight loss and increased CR fitness, as determined by direct measurement of VO2 max. These improvements appear to be time-dependent; thus, exercise testing should be conducted after adequate recovery from BS (>100 days) to achieve optimal CR results. Testing too soon after BS (i.e., during early convalescence) may camouflage potential improvements in functional capacity.