Walk
Away From Diabetes
Study finds modest exercise alone reduces risk factors for Type II
diabetes
Overweight,
middle-aged people who don't exercise are at high risk of Type II
diabetes, but modest exercise alone can improve their odds.
That's the word from
Florida researchers who followed 18 previously sedentary, overweight
subjects for six months. They presented their findings at the American
Diabetes Association's scientific session in San Francisco.
Glen E. Duncan, a
postdoctoral research fellow at the University of Florida who led the
study, says risk factors declined just by adding the exercise and not
improving the diet.
"Even though they did
not lose weight, their insulin sensitivity improved nearly twofold
from when they started," Duncan says.
The better a person's
insulin sensitivity, the lower the risk of getting Type II diabetes,
which now affects about 8 percent of U.S. adults. The more
insulin-resistant a person is, the higher the risk.
The Florida research
follows a much larger study released last year in the New England
Journal of Medicine, in which more than 3,000 subjects in the
Diabetes Prevention Program reduced their risk of Type II diabetes by
58 percent if they adopted intensive lifestyle changes, including a
low-fat diet and daily exercise.
The more recent study
suggests, however, that exercise alone may be a good start.
Duncan and his colleagues
assigned the men and women to different exercise groups. Everyone
walked for 30 minutes a session, but some walked at higher frequencies
-- almost five to seven days a week compared to three to four -- and
higher intensities -- 65 percent to 75 percent of their aerobic
capacity versus 45 percent to 55 percent.
The researchers told the
subjects not to try to lose weight, just to focus on the exercise.
After six months, the researchers took tests such as glucose tolerance
tests and noted BMIs. While the BMIs did not change, the subjects'
insulin sensitivity improved greatly. Levels of an enzyme that helps
in fat metabolism improved, too, Duncan says.
While those at risk for
Type II diabetes should also eventually try to lose weight, Duncan
says exercise may be the best and easiest place to start. "People
have a hard time doing two things, diet and exercise. And even modest
amounts of exercise in the absence of weight loss reduces the risk
factors for Type II diabetes," he says.
"When you use
skeletal muscle [during workouts] it allows insulin to be more
effective at opening the cell door to get the sugar in [from the
bloodstream]," she says. "As we gain more fat cells and
don't exercise our skeletal muscles, the doors to the cells get
'stuck.' The pancreas makes more insulin. Sugar levels rise. This
study underscores the importance of exercise at reversing this insulin
resistance."
