A pre-operative low calorie diet is standard medical care (SC) to improve patient safety during bariatric surgery. Aerobic exercise promotes fitness-mediated metabolic health in obese adults, but it is unknown if fitness can reduce the length of operating time and/or hospital stay (LOS). Thus, we examined if pre-operative exercise plus SC (EX+SC) prior to bariatric surgery improved surgical outcomes versus SC alone.


Fourteen patients (1 Male, 42.3±2.5 y, 45.1±2.5 kg/m2) receiving bariatric surgery were match-paired to SC (n=7) or EX+SC (n = 7; walking 30min/d, 5d/wk, 65-85% HRpeak) for 30 days prior to surgery. A mixed meal tolerance test (MMTT) was performed pre- and post-intervention (~2 d prior to surgery) to assess insulin sensitivity (Matsuda Index) and metabolic flexibility (fed-fasted respiratory exchange ratio). Fitness (VO2peak), body composition (BodPod), and plasma adipokines (adiponectin, leptin) were measured. Omental adipose tissue was collected during surgery to quantify gene expression (PCR) of adiponectin and leptin. Operating time (time from incision to close) and LOS (admission to discharge) was recorded.


SC and EX+SC increased the ratio of high molecular weight to total adiponectin (P=0.05) and tended to raise insulin sensitivity (P=0.10). EX+SC enhanced metabolic flexibility (P=0.01), as well as reduced body fat (P=0.06), total adiponectin (P=0.01), and LOS (EX+SC 41.3±4.4 vs SC 56.7±5.7 hrs; P=0.05) compared to SC. Albeit not significant, VO2peak decreased 5.9% with SC compared to a 2.4% increase with EX+SC (P=0.33), and increased fitness was related to shorter operating time (r=-0.57, P=0.03) and LOS (r=-0.58, P=0.03). Less omental total adiponectin expression correlated with shorter operating time (r=0.71, P=0.02), and low leptin expression was linked to shorter LOS (r=0.65, P=0.03).


Exercise reduced LOS post bariatric surgery, and pre-operative fitness related to improved patient outcomes potentially through an inflammatory mechanism.