The purpose of this study was to compare effects of Roux-en-Y gastric bypass versus a multidisciplinary, group-based medical diabetes and weight management program on physical fitness and behaviors.

Physical behavior and fitness were assessed in participants of the study Surgery or Lifestyle With Intensive Medical Management in the Treatment of Type 2 Diabetes (SLIMM-T2D) (NCT01073020), a randomized, parallel-group trial conducted at a US academic hospital and diabetes clinic with 18- to 24-month follow-up. Thirty-eight type 2 diabetes patients with hemoglobin A_1c ≥6.5% and body mass index 30-42 kg/m² were randomized to Roux-en-Y gastric bypass or the medical program. A 6-minute walk test to evaluate fitness, self-reported physical activity, standardized physical surveys, and cardiometabolic risk assessment were performed at baseline and after intervention.

Both groups similarly improved 6-minute walk test distance, with greater improvements in oxygen saturation and reduced heart rate after surgery. Self-reported physical activity improved similarly at 18-24 months after interventions, although exercise increased gradually after surgery, whereas early substantial increases in the medical group were not fully sustained. Self-reported total and physical health were similar by Short Form-36 but improved more in the Impact of Weight on Quality of Life survey after surgery. Improvement in cardiovascular risk scores, HbA_1c, and body mass index were greater after surgery.

In this small, randomized study, both interventions led to therapeutic lifestyle changes and improved objective and self-reported physical fitness. Greater improvements in heart rate, oxygen saturation, and perceived impact of weight on health were seen after surgery, which could be attributable to greater weight loss. The clinical importance of these improvements with greater weight loss warrants further investigation.