Healthnotes Newswire (January 18, 2007)—Exercise may be as good as diet and drugs at managing diabetes, according to a new study published in Diabetes Care. The effects of aerobic exercise, resistance training, and their combination on glucose control in diabetes are similar to those of dietary, oral drug, and insulin treatments.

“There have been numerous new studies of aerobic, resistance, and combined training,” said Professor Will Hopkins of the Division of Sport and Recreation, Auckland University of Technology in New Zealand, and one of the study’s authors. “We analyzed the collective effects of these three modes of training on [hemoglobin] A1c, the main measure of glucose control in people with diabetes.”

The authors analyzed 27 qualified clinical trials for their review. All trials were placebo-controlled and provided estimates for the effect of aerobic training, resistance training, or combined training on various measures of diabetes control, including hemoglobin A1c.

Also known as glycosylated (or glycated) hemoglobin, the hemoglobin A1c test is an indicator of how much blood sugar has “stuck” to red blood cells, a consequence of prolonged, uncontrolled diabetes. The American Diabetes Association recommends a hemoglobin A1c goal of less than 7.0 percent. The average participant in the study had an initial level of about 8.6 percent.

More than a thousand people with type 2 (adult-onset) diabetes were studied for periods ranging from 5 to 104 weeks. Researchers found no significant differences between aerobic training and resistance training in terms of effects on hemoglobin A1c. For aerobic, resistance, or combined exercise training lasting 12 weeks or more, the overall effect was a small beneficial reduction in hemoglobin A1c. The authors also found small to moderate benefits for other measures of glucose control, which were slightly more pronounced with combined training.

Hopkins and colleagues reported that there are now sufficient studies to conclude that aerobic, resistance, and combined exercise have small to moderate beneficial effects on glucose control in type 2 diabetic patients.

“The reduction in A1c achieved with exercise is small: similar to that with long-term drug therapy, insulin therapy, or dietary changes,” Hopkins said. “However, the combined small effects of drug therapy, diet, and exercise could well be moderate or even large.”

(Diabetes Care 2006;29:2518–27)