The Amount of Weight Loss Six Months after Bariatric Surgery: It Makes a Difference

Background: Bariatric surgery, especially Roux-en-Y gastric bypass (RYGB), has become the most frequently used therapy for morbid obesity. Objectives: The aim of this study was to examine the effects of surgically induced weight loss on cardiopulmonary function 6 months after the procedure, as well as the effect of such an intervention on well-known risk factors for cardiovascular diseases. Methods: This is a cross-sectional study on 66 morbidly obese patients (BMI ≥40 or ≥35 kg/m² with present comorbidities), comparing their cardiopulmonary function prior to and 6 months after RYGB surgery. Results: The substantial amount of weight loss (29.80 ± 13.27 kg) after RYGB surgery was associated with significant reduction of comorbidities, especially diabetes and sedentary lifestyle (p = 0.005 and p = 0.002, respectively). Regarding functional capacity, there was significant increase in peak oxygen uptake (VO₂ peak, p = 0.003), duration of exercise testing, metabolic equivalents (exercise time and METs, p < 0.001), and in peak O₂ pulse. These findings were particularly pronounced in a group of patients who had lost more than 18% of initial weight. Conclusions: Reduction of body weight after RYGB surgery is associated with significantly improved cardiorespiratory function 6 months after surgery, especially in patients who lost more than 18% of their initial body weight. In addition, substantial decreases in body weight were also associated with a reduction of cardiovascular risk factors such as diabetes, smoking, hypertriglyceridemia, and sedentary lifestyle.