Interval training lowered HbA1c in type 2 diabetes

Annual Meeting of the CDA/CSEM

TORONTO — Interval training is an effective method for lowering HbA1c levels in patients with diabetes, according to data from a pilot study.

“We were looking at the effects of high-intensity interval training for individuals with type 2 diabetes,” said Jonathan Little, PhD, a postdoctoral fellow at the University of British Columbia, Okanagan, British Columbia, Canada, who conducted this study as part of his doctoral research while based at McMaster University in Hamilton, Ontario, Canada. “Interval training is becoming a popular method for promoting health benefits.”

The eight participants who were enrolled had diabetes for at least 3 months, a mean age of 63 years, a mean BMI of 32 and were maintained on their medications throughout the intervention. None were on insulin therapy.

Participants underwent continuous glucose monitoring to measure glycemic regulation for 24 hours, and their postprandial glucose responses were measured after meals.

“We were also interested in several aspects of muscle metabolism, looking at markers of glucose transporters and mitochondrial enzymes in muscle,” Little said.

He and colleagues hypothesized that the 2-week intervention would improve HbA1c levels, as well as skeletal muscle metabolic capacity in patients with type 2 diabetes.

Eight participants took part in six interval training sessions during 2 weeks. They initially warmed up for about 3 minutes on a stationary bicycle, then began the 10 intervals, consisting of 1-minute on and 1-minute off training in which 1-minute “on” was exertion at 90% of maximal heart rate. There was a 2-minute cool down period.

The average blood glucose concentration decreased from 7.6 mmol/L to 6.6 mmol/L, and the area under the glucose curve fell by almost 15% after training. The training elevated citrate synthase maximal activity by about 20% and the protein content of cytochrome c oxidase subunit IV by about 68%.

Mitochondrial content in muscle is likely a good indicator of metabolic health for a patient with type 2 diabetes, Little said.

The intervention is one that demands less time from participants than current guidelines for activity: Current guidelines from the Canadian Diabetes Association suggest patients with type 2 diabetes engage in moderate to vigorous aerobic exercise for 150 minutes per week, or 30 minutes five times per week.

Future investigation will likely take the form of a randomized study, Little said. “The next step would be to compare the impact of interval training to the impact of physical activity guidelines of 150 minutes per week.”

For more information:

Little J. #3. Presented at: Annual Meeting of the Canadian Diabetes Association/Canadian Society of Endocrinology and Metabolism; Oct. 26-29, 2011; Toronto.

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