Brisk Daily Walk Improves Metabolic Profile

Peggy Peck
DURHAM, N.C., Dec. 17 -- Walking briskly for 30 minutes a day, six days a week, can significantly reduce blood pressure, waist circumference, triglycerides, and fasting glucose, while increasing HDL, according to researchers here.
Action Points --->
Explain to interested patients that this study confirms earlier reports of the benefit of moderate amounts of daily exercise.
Compared with sedentary adults, those with moderate intensity exercise -- walking 10 to 11 miles over an average 170 minutes a week -- resulted in a significant improvement in metabolic syndrome (P<0.05), said Johanna L. Johnson, M.S., of Duke Medical Center, and colleagues.
Moreover, the benefit was achieved without dietary changes, the investigators reported in the Dec. 15 issue of the American Journal of Cardiology.
But jogging the same distance weekly did not significantly reduce risk compared with men and women who didn't exercise.
"This is an important finding because the data directly addresses the question of how much and what intensity of exercise is needed to obtain metabolic health benefits," the authors wrote.
The authors said they were surprised to discover that increasing intensity -- jogging rather than walking -- for the same distance did not improve metabolic syndrome, but said this suggests that the time spent exercising may be an important consideration.
"It is important to note that this same amount of exercise at a lower intensity required more total minutes a week, which generally led to greater exercise frequency," they wrote. Frequency and duration may, therefore, be important factors in achieving health benefits.
Not surprisingly, the greatest benefit was seen with those who did more vigorous exercise -- on average 19 miles of jogging over a week -- suggesting a dose effect for exercise (P<0.0001).
The STRRIDE (Studies of a Targeted Risk Reduction Intervention through Defined Exercise) trial recruited 334 middle-age, overweight men and women who were randomized to one of three eight-month training regimens or to a six-month control group. Two-hundred and twenty-seven participants completed the trial and the study findings were culled from analysis of complete data from 171 participants.
The exercise interventions were: low amount/moderate intensity (equivalent to walking about 12 miles a week), low amount/vigorous intensity (jogging 12 miles a week), and high amount/vigorous intensity (jogging 19 miles a week).
All the exercise groups underwent two to three months of conditioning in which the exercise amount and intensity were gradually increased in order to minimize injury. The ramp-up period was followed by six months of training at the assigned exercise prescription.
At baseline, women generally had more favorable cardiovascular profiles than men, the authors said (34% of women met metabolic syndrome criteria versus 46% of men), but both men and women benefited from exercise.
The authors cautioned that although the findings are generally applicable, they might not be appropriate for "special populations, such as those with hypertension, diabetes, or cardiovascular disease."
The study was funded by the National Institutes of Health. The authors declared no conflicts.
Primary source: American Journal of CardiologySource reference:Johnson JL, "Exercise training amount and intensity effects on metabolic syndrome (from Studies of a Targeted Risk Reduction Intervention through Defined Exercise)" Am J Cardiol 2007; DOI: 10.1016/j.amjcard.2007.07.027.