Tuesday, December 20, 2011

Thirty Minutes of Exercise Per Week May Help Type 2 Diabetes


December 20, 2011 
Jonathan Little
written by Michael O’Leary
Can’t do 150 minutes of exercise per week? Maybe 30 minutes of intense training each week can help control your type 2 diabetes.
If you have type 2 diabetes and find it hard to fit in the 150 minutes of moderate to vigorous exercise a week recommended by the American Diabetes Association, there may be a way to get as much benefit from 30 minutes a week, a small new study suggests.
Led by Jonathan Little, of the Departments of Kinesiology and of Pediatrics and Medicine at McMaster University, Ontario, the researchers found that six high-intensity training sessions totaling only 30 minutes per week for two weeks rapidly reduced high blood sugar and increased the capacity of skeletal muscles to use oxygen. (Link to published site)
“While longer-term comparative studies are clearly warranted,” the researchers wrote, “our findings indicate that low-volume high-intensity training may represent a time-efficient exercise strategy for the treatment of type 2 diabetes.” Their findings appeared online in the December issue of the Journal of Applied Physiology.
In the study, reported on by News-Medical.net, 8 volunteers with type 2 diabetes underwent a starting fitness assessment that included a blood sugar test over a 24-hour period and biopsies of thigh muscle to measure protein levels within muscle cells that are markers of metabolic health.
The exercise program involved six supervised stationary bicycle sessions that consisted of 10 repetitions of 60 seconds each. For each repetition participants raised their heart rate to 90 percent of their maximum heart rate for their age, and then rested for 60 seconds. After the 10th repetition, they performed a short warm-up and cool-down. Each session lasted 25 minutes with only 10 minutes performing high-intensity exercise. These sessions were repeated three times a week for total of 30 minutes of high-intensity training within a total of 75 minutes of overall training per week.
After two weeks of this program, the researchers reassessed each participant’s fitness level, blood sugar, and exercise capacity as measured by the muscle biopsies. They found that all of the volunteers lowered their 24-hour average blood sugar concentrations from an average of 7.6 percent to 6.6 percent, and lower blood sugar spikes after meals from an average of 965 mmol/l to an average of 679 mmol/l. (A millimole is a scientific measure of molecules or atoms of a given substance. One mole is the number 6 followed by 23 zeroes, a millimole is one-thousandths of a mole.)
The muscle biopsies showed higher amounts of the cell proteins indicating greater metabolic health and a change in relative composition of fat and muscle in the body, which the researchers suggested might explain why there was no significant decrease in body mass.  Participants did, however, achieve a decreased heart rate during exercise, a marker of improved fitness and greater capacity to exercise.
The researchers acknowledge that much larger studies will be needed to confirm these results and identify the biological mechanism behind these results.
“Given that the majority of individuals with and without type 2 diabetes do not accumulate sufficient exercise to achieve health benefits, and the most common cited barrier to regular exercise is a lack of time,” the researchers wrote, “our results suggest that low-volume high-intensity training may be a viable, time-efficient strategy to improve health in patients with type 2 diabetes.”

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