Combined Aerobic and Resistance Training Helps Patients With Diabetes

Performing a combination of aerobic exercise and resistance training was associated with improved glycemic levels among patients with type 2 diabetes compared to patients who did not exercise, according to a study in a recent issue of JAMA. The level of improvement was not seen among patients who performed either aerobic exercise or resistance training alone.

Although it is generally accepted that regular exercise provides substantial health benefits for individuals with type 2 diabetes, the exact exercise type (aerobic vs resistance vs both) has been unclear.

Timothy S. Church, MD, MPH, PhD, of Louisiana State University, Baton Rouge, and colleagues conducted the HART-D trial, which compared among 262 sedentary women and men with type 2 diabetes the effect of aerobic training, resistance training, and a combination of both on change in hemoglobin A1c levels (HbA1c; a minor component of hemoglobin and to which glucose is bound; HbA1c levels are used to monitor the control of diabetes mellitus). Study participants were 63.0% women, 47.3% nonwhite, aged 56 years on average, and had an HbA1c level of 7.7% and a duration of diabetes of 7.1 years. The individuals were enrolled in the 9-month exercise program between April 2007 and August 2009. Forty-one participants were assigned to the nonexercise control group, 73 to resistance training sessions, 72 to aerobic exercise sessions, and 76 to combined aerobic and resistance training.

The researchers found that the absolute change in HbA1c in the combination training group vs the control group was -0.34%. In neither the resistance training (-0.16%) nor the aerobic (-0.24%) groups were changes in HbA1c significant compared with those in the control group. The prevalence of increases in hypoglycemic medications were 39% in the control, 32% in the resistance training, 22% in the aerobic, and 18% in the combination training groups.

Compared with the control group, only the combination-training group improved maximum oxygen consumption. In all exercise groups, waist circumference decreased from -.75 to -1.1 inches compared with the control group. The resistance-training group lost an average of 3.1 lbs fat mass, and the combination-training group lost an average of 3.7 lbs compared with the control group.

The primary finding from this trial is that although both resistance and aerobic exercise provide benefits, only the combination resulted in reductions in HbA1c levels. It is also significant that the difference in HbA1c between the combination training group and the control group at follow-up occurred even though the control group had increased its use of diabetes medications and the combination-training group decreased its diabetes medication use.