Walking briskly on a regular basis may be more effective than vigorously jogging for people with pre-diabetes, a new study has found. The findings are the result of a six-month study of 150 participants, each of whom was designated as having pre-diabetes based on elevated fasting glucose levels.
Study participants were randomised into four groups. The first group followed an intervention modeled after the Diabetes Prevention Programme (DPP), considered a gold standard, that aims to achieve a 7 per cent body weight reduction over 6 months.
The programme requires cutting calories, eating a low-fat diet, and exercising. Study participants in this group adopted the diet changes, and performed moderate-intensity exercise equivalent to 12 km of brisk walking in a week.
Other study participants were randomly assigned to receive exercise only, using different amounts and intensities - low-amount at moderate intensity (equivalent to walking briskly for 12 km per week); high-amount at moderate intensity (equivalent to walking briskly for 18.5 km per week); and high-amount at vigorous intensity (equivalent to jogging for 18.5 km per week).
"We know the benefits of lifestyle changes from the DPP, but it is difficult to get patients to do even one behavior, not to mention three," said William Kraus, professor of medicine at Duke University School of Medicine in the US. "We wanted to know how much of the effect of the DPP could be accomplished with exercise alone, and which intensity of exercise is better for controlling metabolism in individuals at risk for diabetes," Kraus said.
Participants in the DPP group had the greatest benefit, with a 9 per cent improvement in oral glucose tolerance – a key measure of how readily the body processes sugar and an indicator used to predict progression to diabetes.
One of the exercise-only groups came in a close second. Participants in the moderate-intensity, 18.5 km group saw a 7 per cent improvement in glucose tolerance on average. The moderate-intensity, 12 km group had a 5 per cent improvement on average.
The lowest improvement was seen among those in the vigorous-intensity, 18.5 km group, with only a 2 per cent average improvement.
"Another way to say it is that a high amount of moderate-intensity exercise alone provided nearly the same benefit on glucose tolerance that we see in the gold standard of fat and calorie restriction along with exercise," said Cris Slentz, assistant professor at Duke.
"High-intensity exercise tends to burn glucose more than fat, while moderate-intensity exercise tends to burn fat more than glucose," Kraus said.
"We believe that one benefit of moderate-intensity exercise is that it burns off fat in the muscles, which relieves the block of glucose uptake by the muscles, he said. "That's important because muscle is the major place to store glucose after a meal," Kraus said.