Exercise can reduce HbA1c in Type 2 diabetics
MedWire News: Results from a meta-analysis published in JAMA show that aerobic exercise, resistance training, or a combination of the two can significantly reduce glycated hemoglobin (HbA1c) levels in patients with Type 2 diabetes.
Although all patients who exercised benefitted through reductions in HbA1c, the researchers found that individuals who performed more than 150 minutes of structured exercise per week had a greater reduction in HbA1c than those who underwent less.
Beatriz Schaan (Federal University of Rio Grande do Sul, Porto Alegre, Brazil) and colleagues selected 47 randomized controlled trials including 8538 adult patients with Type 2 diabetes for their analysis.
They included studies that were randomized controlled trials, compared performance of structured exercise (aerobic exercise, resistance training, or a combination of both) or receipt of physical activity advice with no exercise intervention, and measured change in HbA1c as an outcome. The trials were all of at least 12 weeks in duration.
When compared with controls who did not follow a structured exercise program, patients who performed structured exercise (23 studies) had a significant 0.67% greater reduction in HbA1c at the end of the study period.
Similarly, patients who received physical activity and dietary advice (24 studies) also had a significantly greater reduction in HbA1c than controls, by 0.58%.
The individual categories of aerobic exercise, resistance training, or a combination of the two were also associated with significantly greater reductions in HbA1c compared with control treatment, by 0.73%, 0.57%, and 0.51%, respectively.
When Schaan and team divided the pooled participants up according to amount of time spent doing exercise per week, longer duration of exercise had more of an effect than shorter duration. More specifically, patients who performed 150 minutes of exercise or more per week had a reduction in HbA1c of 0.89% compared with controls, whereas those who did less exercise had a reduction of 0.36%.
The researchers explain that this difference is important as current guidelines suggest patients should perform at least 150 minutes per week.
Schaan and colleagues primarily assessed the mean difference in HbA1c achieved between patients performing exercise and controls, but they do note that patients with a baseline HbA1c of greater than 7% appeared to gain more benefit from exercise than those with a lower HbA1c on enrollment.
"Because HbA1c reduction in Type 2 diabetes is associated with improved insulin resistance, and both exercise training/physical activity and body weight reduction induced by low-calorie diets have distinct mechanisms to elicit these effects, it is expected that these interventions applied together would result in greater metabolic effects," write the authors.
"Therefore, patients with Type 2 diabetes should receive dietary recommendations in combination with advice to increase physical activity," they conclude.
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By Helen Albert