Supervised Exercise Program Improves HbA1c Levels in Diabetic Patients

November 12, 2010

November 11, 2010 (Rome, Italy) — A structured, supervised exercise program effectively improves HbA1c levels and the cardiovascular risk profile of individuals with diabetes mellitus, a new study shows [1]. The exercise program, a twice-weekly, facility-based regimen that included aerobic exercise, resistance training, and counseling was significantly better at improving HbA1c levels and cardiovascular risk factors than a treatment regimen that only counseled physical activity.

"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," write lead investigator Dr Stefano Balducci (La Sapienza University, Rome, Italy) and colleagues in the November 8, 2010 issue of the Archives of Internal Medicine.

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 HbA1c 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

Variable Control, 12 mo Exercise arm, 12 mo Mean difference p, exercise versus control
Total physical activity (MET-h/wk) 10.0 20.0 10.0 <0.001
Unsupervised physical activity (MET-h/wk) 10.0 12.5 2.47 <0.001
HbA1c (%) 7.02 6.70 -0.30 <0.001
Systolic blood pressure (mm Hg) 138 132 -4.2 0.002
Diastolic blood pressure (mm Hg) 83 80 -1.7 0.03
Triglycerides (mg/dL) 141 132 -6.7 0.85
HDL (mg/dL) 45.6 48.4 3.7 <0.001
LDL (mg/dL) 114 106 -9.6 0.003
Body-mass index 31.7 30.3 -0.78 <0.001

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 HbA1c levels and the cardiovascular risk profile of these high-risk individuals.

Is More Needed?

Of note, 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.

In an editorial accompanying the study [2], Dr Ronald Sigal (University of Calgary, AB) and Dr Glen Kenny (University of Ottawa, ON) 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."

The IDES authors and editorialists report no conflicts of interest.