Clinical trial demonstrates exercise following bariatric surgery improves insulin sensitivity

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Abstract

BACKGROUND. Roux-en-Y gastric bypass (RYGB) surgery causes profound weight loss and improves insulin sensitivity (S_I) in obese patients. Regular exercise can also improve S_I in obese individuals; however, it is unknown whether exercise and RYGB surgery–induced weight loss would additively improve S_I and other cardiometabolic factors.

METHODS. We conducted a single-blind, prospective, randomized trial with 128 men and women who recently underwent RYGB surgery (within 1–3 months). Participants were randomized to either a 6-month semi-supervised moderate exercise protocol (EX, n = 66) or a health education control (CON; n = 62) intervention. Main outcomes measured included S_I and glucose effectiveness (S_G), which were determined from an intravenous glucose tolerance test and minimal modeling. Secondary outcomes measured were cardiorespiratory fitness (VO₂ peak) and body composition. Data were analyzed using an intention-to-treat (ITT) and per-protocol (PP) approach to assess the efficacy of the exercise intervention (>120 min of exercise/week).

RESULTS. 119 (93%) participants completed the interventions, 95% for CON and 91% for EX. There was a significant decrease in body weight and fat mass for both groups (P < 0.001 for time effect). S_I improved in both groups following the intervention (ITT: CON vs. EX; +1.64 vs. +2.24 min^–1/μU/ml, P = 0.18 for Δ, P < 0.001 for time effect). A PP analysis revealed that exercise produced an additive S_I improvement (PP: CON vs. EX; +1.57 vs. +2.69 min^–1/μU/ml, P = 0.019) above that of surgery. Exercise also improved S_G (ITT: CON vs. EX; +0.0023 vs. +0.0063 min^–1, P = 0.009) compared with the CON group. Exercise improved cardiorespiratory fitness (VO₂ peak) compared with the CON group.

CONCLUSION. Moderate exercise following RYGB surgery provides additional improvements in S_I, S_G, and cardiorespiratory fitness compared with a sedentary lifestyle during similar weight loss.

TRIAL REGISTRATION. clinicaltrials.gov identifier: NCT00692367.

FUNDING. This study was funded by the NIH/National Institute of Diabetes and Digestive and Kidney Diseases (R01 DK078192) and an NIH/National Center for Research Resources/Clinical and Translational Science Award (UL1 RR024153).

Authors

Paul M. Coen, Charles J. Tanner, Nicole L. Helbling, Gabriel S. Dubis, Kazanna C. Hames, Hui Xie, George M. Eid, Maja Stefanovic-Racic, Frederico G.S. Toledo, John M. Jakicic, Joseph A. Houmard, Bret H. Goodpaster