title: Differential changes in exercise performance after massive weight loss induced by bariatric surgery.
abstract: BACKGROUND
  Exercise performance and pulmonary function are often impaired in severely obese subjects. Bariatric surgery represents the most effective therapy for severe obesity, but data on changes in exercise performance after massive weight loss induced by bariatric surgery have rarely been assessed so far.
  
  
  METHODS
  Exercise performance was obtained by bicycle spiroergometry in 18 severely obese patients before and at least 1 year after bariatric surgery. Additionally, pulmonary function was assessed by spirometry.
  
  
  RESULTS
  BMI was reduced from 46.3 ± 1.6 to 33.5 ± 1.4 kg/m(2) after surgery. Pulmonary function (forced expiratory volume within 1 s; inspiratory vital capacity) improved after weight loss (both p ≤ 0.01). At peak exercise, heart rate (HR) peak, absolute oxygen uptake (VO(2)) peak, and load peak did not differ between both assessments (all p > 0.25). However, relative (related to actual body weight) VO(2) peak and workload peak were higher after than before surgery (both p ≤ 0.005), while gross efficiency peak and ventilatory equivalent peak remained unchanged (both p > 0.30). At anaerobic threshold (AT), patients showed lower HR AT and absolute VO(2) AT after than before surgery (both p < 0.05), while absolute workload AT did not differ (p = 0.58). In turn, relative VO(2) AT did not change (p = 0.30), whereas relative workload AT was higher after surgery (p = 0.04). Also, ventilatory efficiency AT and gross efficiency AT tended to be improved (both p = 0.08). Before surgery, the patients performed 27.0 % of VO(2) peak above their AT, while this fraction increased to 35.3 % (p = 0.006).
  
  
  CONCLUSIONS
  Results indicated differential changes in exercise performance, with the relative but not the absolute peak performance being improved after massive weight loss. Interestingly, anaerobic exercise tolerance was markedly improved after surgery.
authors.affiliation: Interdisciplinary Obesity Center, Department of Surgery, Cantonal Hospital St. Gallen, Heidener Str. 11, 9400, Rorschach, Switzerland.
authors.forename: Britta
authors.initials: B
authors.lastname: Wilms
authors.forename: Barbara
authors.initials: B
authors.lastname: Ernst
authors.forename: Martin
authors.initials: M
authors.lastname: Thurnheer
authors.forename: Burkhard
authors.initials: B
authors.lastname: Weisser
authors.forename: Bernd
authors.initials: B
authors.lastname: Schultes
mesh_terms: D000328:Adult; D050110:Bariatric Surgery; D015992:Body Mass Index; D001835:Body Weight; D015444:Exercise; D005080:Exercise Test / Q000379:methods; D017079:Exercise Tolerance; D005260:Female; D006801:Humans; D008297:Male; D009767:Obesity, Morbid / Q000453:epidemiology / Q000503:physiopathology* / Q000601:surgery; D010101:Oxygen Consumption; D011184:Postoperative Period; D057234:Preoperative Period; D012129:Respiratory Function Tests; D013147:Spirometry; D013557:Switzerland / Q000453:epidemiology; D015431:Weight Loss