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01-28-2009, 01:31 PM
Brief but Intense Exercise May Thwart Diabetes
By Charles Bankhead, Staff Writer, MedPage Today
EDINBURGH, Scotland, Jan. 28 -- As little as three minutes of high-intensity exercise every other day may help sedentary people ward off diabetes, results of a small clinical study suggested.
owledged a lack of agreement about the optimal exercise regimen.
Two weeks of brief episodes of high-intensity training led to significant (P<0.01 to P<0.001) improvement in multiple parameters of blood glucose and insulin action in healthy volunteers, James A. Timmons, of Heriot-Watt University here, and colleagues reported online in BMC Endocrine Disorders.
The six training sessions lasted a total of 15 minutes.
"The efficacy of a high-intensity exercise protocol, involving only about 250 kcal of work each week, to substantially improve insulin action in young sedentary subjects is remarkable," the authors concluded.
"This novel time-efficient training paradigm can be used as a strategy to reduce metabolic risk factors in young and middle-aged sedentary populations who otherwise would not adhere to time-consuming traditional aerobic exercise regimes," they said.
The risk of cardiovascular disease and type 2 diabetes can be reduced by regular physical activity. However, no consensus exists as to the optimal amount or intensity of activity required to improve the risk profile, the authors noted.
Recommendations for improved glycemic control typically emphasize several hours of moderate or vigorous exercise each week, a goal ignored by the general population because of lack of time, motivation, and adherence, the authors said.
Recently, low-volume, high-intensity interval training has been suggested as a time-efficient exercise protocol to improve aerobic fitness, they continued.
"We speculated that it should be possible to substantially improve insulin action using high-intensity interval training despite a negligible contribution to total energy expenditure as this training model would substantially reduce muscle glycogen stores."
To test their hypothesis, the authors recruited 16 healthy young men (median age 21) to participate in a trial of high-intensity interval training. None of the volunteers was involved in a structured program of physical activity.
Over the course of two weeks, the participants completed six sessions of supervised high-intensity interval training. Each session consisted of four to six 30-second sprints on a stationary bicycle.
At baseline and at the end of the two weeks, the authors assessed the participants' aerobic performance in a self-paced cycling time trial, as well as glucose, insulin and non-esterified fatty acids response to a 75-g oral glucose tolerance test.
The end-of-study measurements showed significant improvement in each parameter of glucose tolerance.
Compared with baseline values, the area under the time-concentration curves for plasma glucose, insulin, and non-esterified fatty acids were reduced by 12%, 37%, and 26%, respectively (P<0.001 for each value).
Fasting plasma insulin and glucose values remained unchanged, but non-esterified fatty acid concentrations had decreased by 60
By Charles Bankhead, Staff Writer, MedPage Today
EDINBURGH, Scotland, Jan. 28 -- As little as three minutes of high-intensity exercise every other day may help sedentary people ward off diabetes, results of a small clinical study suggested.
owledged a lack of agreement about the optimal exercise regimen.
Two weeks of brief episodes of high-intensity training led to significant (P<0.01 to P<0.001) improvement in multiple parameters of blood glucose and insulin action in healthy volunteers, James A. Timmons, of Heriot-Watt University here, and colleagues reported online in BMC Endocrine Disorders.
The six training sessions lasted a total of 15 minutes.
"The efficacy of a high-intensity exercise protocol, involving only about 250 kcal of work each week, to substantially improve insulin action in young sedentary subjects is remarkable," the authors concluded.
"This novel time-efficient training paradigm can be used as a strategy to reduce metabolic risk factors in young and middle-aged sedentary populations who otherwise would not adhere to time-consuming traditional aerobic exercise regimes," they said.
The risk of cardiovascular disease and type 2 diabetes can be reduced by regular physical activity. However, no consensus exists as to the optimal amount or intensity of activity required to improve the risk profile, the authors noted.
Recommendations for improved glycemic control typically emphasize several hours of moderate or vigorous exercise each week, a goal ignored by the general population because of lack of time, motivation, and adherence, the authors said.
Recently, low-volume, high-intensity interval training has been suggested as a time-efficient exercise protocol to improve aerobic fitness, they continued.
"We speculated that it should be possible to substantially improve insulin action using high-intensity interval training despite a negligible contribution to total energy expenditure as this training model would substantially reduce muscle glycogen stores."
To test their hypothesis, the authors recruited 16 healthy young men (median age 21) to participate in a trial of high-intensity interval training. None of the volunteers was involved in a structured program of physical activity.
Over the course of two weeks, the participants completed six sessions of supervised high-intensity interval training. Each session consisted of four to six 30-second sprints on a stationary bicycle.
At baseline and at the end of the two weeks, the authors assessed the participants' aerobic performance in a self-paced cycling time trial, as well as glucose, insulin and non-esterified fatty acids response to a 75-g oral glucose tolerance test.
The end-of-study measurements showed significant improvement in each parameter of glucose tolerance.
Compared with baseline values, the area under the time-concentration curves for plasma glucose, insulin, and non-esterified fatty acids were reduced by 12%, 37%, and 26%, respectively (P<0.001 for each value).
Fasting plasma insulin and glucose values remained unchanged, but non-esterified fatty acid concentrations had decreased by 60