Effects of a 12-week moderate-intensity exercise training on blood glucose response in patients with type 2 diabetes: A prospective longitudinal study.

Background: The blood glucose response to moderate-intensity exercise remains unclear for patients with type 2 diabetes (T2DM). In addition, little is known about determinants of blood glucose response to a 12-week moderate-intensity exercise training. Therefore, this study aimed to explore trends in blood glucose in response to a 12-week moderate-intensity exercise training in patients with T2DM and to explore the predictors of post-exercise blood glucose (PEBG) and exercise-induced glucose response (EIGR).

Methods: A prospective longitudinal study was conducted. Of the 66 participants with T2DM recruited from outpatient clinics of a medical center, 20 were eligible to enroll in a 12-week moderate-intensity exercise training. Participants were randomly assigned to 1 of 3 exercise times (morning, afternoon, or evening). Blood glucose were measured pre- and post-exercise. The EIGR was calculated by subtracting the PEBG from the before-exercise blood glucose (BEBG). Generalized estimating equations were used to examine the trends and predictors of PEBG and EIGR.

Results: The BEBG declined progressively (β = -1.69, P < .001); while the PEBG (β = -0.18, P = .08) remained stable over time during the 12-week exercise training. Higher BEBG predicted higher (β = 0.53, P < .001) PEBG. Higher baseline maximum oxygen uptake (VO2max) contributed to a larger magnitude of EIGR; higher HgbA1c and BEBG predicted higher EIGR (β = 0.27, P = .02; β = 0.45, P < .001); afternoon or evening exercise predicted lower (β = -13.2, P = .04; β = -5.96, P = .005) EIGR than did morning exercise.

Conclusions: A 12-week moderate-intensity exercise training appears safe for patients with T2DM. Time of day for exercise, baseline VO2max, and baseline metabolic control may influence the impact of exercise for individuals with T2DM. These findings provide considerations for design of optimal exercise training for T2DM patients.