Study Shows Combination of Aerobic and Resistance Training Improves A1C Levels in People with Type 2 Diabetes
A study conducted in people with type 2 diabetes showed performing a combination of aerobic exercise and muscle-strengthening, or resistance, training was more effective in lowering hemoglobin A1c, also called glycated hemoglobin or A1C, levels than either type of exercise alone.
The Health Benefits of Aerobic and Resistance Training in individuals with type 2 diabetes (HART-D) study was conducted by researchers at the Pennington Biomedical Research Center of the Louisiana State University System, led by Timothy S. Church, M.D., M.P.H., Ph.D., director of preventive medicine research.
The value of regular exercise for people with type 2 diabetes is well recognized. However, according to the authors, the best types—or combination of types—of exercise has been unclear.
The HART-D study assessed the effects of aerobic training, resistance training, and a combination of both on changes in A1C levels among 262 sedentary men and women with type 2 diabetes. Study participants were enrolled in a 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 a combination of aerobic exercise and resistance training.
“Our two most important goals in developing exercise doses for HART-D were to keep the total duration of weekly exercise similar across groups while ensuring that the aerobic prescriptions met current guidelines,” said Church. “We achieved both goals, and our findings strongly support the 2008 Federal Physical Activity Guidelines for Americans recommendation that optimal physical activity programs consist of regular physical activity combined with resistance training.”
At the end of the study, researchers found that the combination exercise group had A1C levels 0.34 percent lower than those of the control group. This statistically significant change occurred even though the control group had increased its use of diabetes medications and the combination exercise group had decreased its use of the medications. Neither the resistance training group nor the aerobic exercise group showed significant A1C changes when compared with those of the control group.
All exercise groups reduced waist circumference compared with the control group. The resistance training group lost an average of 3.1 pounds (lbs.) of fat mass and the combination exercise group lost an average of 3.7 lbs., compared with the control group.
“This study’s primary finding was that although both resistance and aerobic training provide benefits, only the combination of the two was associated with significant reductions in A1C levels,” said Church.
As noted by the HART-D study’s authors, the 2008 Federal Physical Activity Guidelines for Americans, published by the U.S. Department of Health and Human Services, recommend aerobic exercise in combination with resistance training for most people. The guidelines, available at www.health.gov/PAGuidelines, provide information and guidance about the types and amounts of physical activity that provide substantial health benefits for Americans ages 6 years and older.
The National Institute of Diabetes and Digestive and Kidney Diseases (NIDDK) provided grant funding for the HART-D study under National Institutes of Health clinical trial number NCT00458133. Visit www.clinicaltrials.gov/ct2/show/NCT00458133 for more information.The NIDDK has easy-to-read booklets and fact sheets about diabetes. For more information or to obtain copies, visit www.diabetes.niddk.nih.gov.
NIH Publication No. 12–4562
Page last updated: December 19, 2011