A Little Brisk Walking Gives Benefits to the Sedentary

BELFAST, Ireland -- Sedentary adults who took a brisk half-hour walk on only three days a week lost weight and were rewarded with improved fitness and cardiovascular benefits, researchers reported.

BELFAST, Ireland, Aug. 14 -- Sedentary adults who took a brisk half-hour walk on only three days a week lost weight and were rewarded with improved fitness and cardiovascular benefits, researchers reported.

The three-day walking program produced a significant reduction in systolic blood pressure, weight, and an increase in functional capacity after 12 weeks, Mark A. Tully, Ph.D., of Queen's University in Belfast, and colleagues, reported in the Journal of Epidemiology and Community Health.

Few meet the current minimum exercise recommendation of 30 minutes of exercise five days a week, citing lack of time, the investigators noted. But the unsupervised three-month home-based program of brisk walking for 30 minutes three days a week demonstrated that less may be better than nothing.

Those who walked five days a week, the current recommended level, improved in these measures as well, and also had a decrease in diastolic blood pressure, the researchers reported.

To determine the short-term effects of walking at and below the current recommended exercise levels, the researchers randomized 106 healthy, sedentary men and women, ages 40 to 61, to a three-month walking program.

There were 44 participants taking a brisk walk for 30 minutes three days a week, 42 doing so five days a week, and 20 in a sedentary control group.

Participants could choose to walk in bouts of at least 10 minutes, and used pedometers to record the number of steps taken.

Blood samples were analyzed for lipid levels, while waist and hip circumferences were measured with standard procedures.

Functional capacity was measured by a 10-meter shuttle walk test. Participants walked between two cones in response to a series of beeps of increasing frequency until they could no longer achieve the pace set.

Of the 106 participants, 93 completed the study, the researchers wrote.

Systolic blood pressure and waist and hip circumferences fell significantly both in the three-day group (5 mm Hg, 2.6 cm, and 2.4 cm, respectively) and in the five day group (6 mm Hg, 2.5 cm, and 2.2 cm) (P

To determine whether the significant changes in weight and BMI seen in the three-day group, but not in the five-day group, were a result of sex imbalance within the groups, the researchers did an analysis and found no significant differences.

Analysis of the food frequency diaries also showed no changes in any of the groups. Future studies, the researchers said, might use stratification by sex to avoid potential confounding effects.

Also, no significant changes in waist-hip ratios, associated with a risk of myocardial infarction, were found, possibly because of lack of powering in an insufficient sample size.

The reductions in systolic and diastolic blood pressure in the five-day group are similar to those reported in a meta-analysis of 16 studies, the researchers wrote.

The findings from this study, they added, indicate that the reduction in systolic blood pressure (6 mm Hg in the five-day group, and 4.5 mm Hg in the three-day group) are in themselves clinically significant in reducing the risk of vascular mortality.

Study limitations included the fact that walking was self-reported and the pace was self-selected. It was also possible that the three-day group did more exercise than they reported as the study design did not include an objective measure of all activity undertaken during the study, and this would require further exploration.

The walkers' motivation to demonstrate improvement may also have influenced their performance, the researchers said.

The results of this study may encourage people who feel they do not have time to exercise five days a week to consider a lower weekly target of exercise, or of taking an opportunity for short bouts of physical activity.

Further studies are needed of the longer effects of low levels of exercise and of unsupervised home-based walking for a wider community and should be large enough to allow detection of meaningful changes in a spectrum of cardiovascular risk factors, the researcher wrote.