Supervised Exercise Program Improves Hba1c Levels in Diabetic Patients

Lead investigator Dr. Stefano Balducci (La Sapienza University, Rome, Italy) and colleagues write, "In fact, supervised training on top of structured counseling was superior to counseling alone in increasing the amount of nonsupervised physical activity, thus suggesting that the twice-a-week sessions supervised by an exercise specialist served as continuous reinforcement to counseling." 

The study, known as the Italian Diabetes and Exercise Study (IDES), included 606 patients enrolled in 22 outpatient diabetes clinics across Italy and randomized them to one of two treatment regimens. In the first treatment arm, patients were randomized to twice-a-week supervised aerobic and resistance training plus structured exercise counseling, with each supervised exercise session lasting 75 minutes. Patients in the second arm (control) received structured physical activity counseling by trained physicians every three months.

These results might imply that the amount of physical activity that is required to effectively reduce cardiovascular burden in these high-risk subjects could be higher than the minimum recommended.

After 12 months, compared with the counseling group plus usual care, those undergoing supervised exercise training had significantly lower HbA_1c levels -- a significant 0.30% difference between the two groups at 12 months -- as well as improved markers of cardiovascular risk, such as LDL- and HDL-cholesterol levels.

Change in Risk Factors between the Control and Exercise Groups

MET=metabolic equivalent

The researchers point out that the trial is larger and of longer duration than previously published exercise intervention trials in diabetes and provides "definitive evidence that exercise is highly effective" in improving HbA_1c levels and the cardiovascular risk profile of these high-risk individuals.

Balducci and colleagues point out that those who underwent exercise counseling alone successfully achieved the currently recommended target for physical activity, that being 150 minutes of moderate to intense activity per week, corresponding to 11.25 MET-hours/week, and while this activity improved cardiorespiratory fitness levels in these previously sedentary subjects, it was not enough to improve glycemic control or improve their cardiovascular risk profile.

"These results might imply that the amount of physical activity that is required to effectively reduce cardiovascular burden in these high-risk subjects could be higher than the minimum recommended," write the authors.

Dr. Ronald Sigal (University of Calgary, AB) and Dr. Glen Kenny (University of Ottawa, ON), in an editorial accompanying the study praised the IDES investigators, noting that it builds on the findings of previous trials and supports the addition of supervised, facility-based exercise training to standard therapy for Type 2 diabetes mellitus, "just as exercise-based cardiac rehabilitation is considered part of the optimal treatment of patients with acute cardiac events."

The editorialists say the costs of the exercise program should be covered by payers and insurers and would compare favorably with the costs of diabetes drugs, "none of which would have the vast range of clinically beneficial effects demonstrated in the IDES supervised exercise group."

1. Balducci S, Zanuso S, Nicolucci A, et al. Effect of an intensive exercise intervention strategy on modifiable cardiovascular risk factors in subjects with Type 2 diabetes. Arch Intern Med 2010; 170:1794-1803.
2. Sigal RJ, Kenny GP. New evidence for the value of supervised exercise training in Type 2 diabetes mellitus. Arch Intern Med 2010; 170:1790-1791.