Effects of Exercise-Based Cardiac Rehabilitation on Hemoglobin A1c Levels in Type II Diabetics

Abstract

Regular physical activity favorably modifies blood glucose (BG) and hemoglobin A1c (A1c) values in Type II diabetic (DM) patients (pts). Few data are available regarding the impact of exercise-based cardiac rehabilitation (CR) on BG and A1c levels in pts with Type II DM. PURPOSE: To evaluate the effects of exercise training (50-70% heart rate reserve, 50-60 min/session, >3 days/wk) on BG and A1c in Type II DM pts in Phase II CR. The impact of concomitant dietary counseling was evaluated in a randomized subset of pts. METHODS: Fifty, consecutive Type II DM pts, aged 35-81, were enrolled. A1c was assessed during the initial visits (v) and following 12 weeks of exercise training. Pre- and post-exercise BG values were collected at v2, at the completion of CR (v18) and at 12 weeks (final) following additional self-monitored exercise training. Half of the pts (n = 25) were randomized to dietary counseling (DC) in addition to exercise (E+DC), the remaining pts (n = 25) received exercise only (EO). Eight pts were lost to follow-up. RESULTS: A comparison of initial versus final values for A1c revealed no significant reduction in either group. The E+DC group demonstrated a significant reduction (P = 0.014) in pre-exercise BG between v2 and v18; in contrast, the decrease in EO was modest and insignificant, perhaps due to a lower BG mean value at the program inception.Table: No caption provided.CONCLUSION: These findings suggest that dietary counseling, when superimposed on exercise-based cardiac rehabilitation, may have favorable effects on pre-exercise BG levels in pts with Type II DM. In contrast, neither intervention elicited favorable improvement in modestly elevated baseline A1c levels.