Moderate, less frequent exercise can drive down blood pressure and boost overall fitness, according to the study, which is published in the Journal of Epidemiology and Community Health.

Current Recommendation: 5 Days a Week

The prevailing wisdom is that adults should engage in moderately strenuous exercise for 30 minutes at least five days a week. This is a target that many people don't hit -- most often due to constraints on time.

Mark A Tully, PhD, and colleagues recruited 106 healthy but sedentary individuals aged 40 to 60 to undertake a 12-week exercise program for the study.

Eighty-six participants were assigned to walk briskly for 30 minutes -- 44 on five days and 42 on just three days a week. The remaining participants were instructed to maintain their normal lifestyle.

Blood pressure, blood cholesterol, weight, hip and waist girth, and overall fitness (functional capacity) were measured at the start and finish of the study.

Most people -- 89 percent -- completed the program.

Lighter Regimens Still Help

Blood pressure and hip and weight measurements fell significantly in both groups of walkers, the researchers reported, and their overall fitness improved. However, there were no changes observed among the non-walkers. Even small decreases in blood pressure, hip and waist measurements can lower a person's risk of dying from heart disease, the authors pointed out.

"This study shows short-term benefits of unsupervised home-based walking programs both at and below the currently recommended minimum target level of exercise," say the authors.

"The results may encourage people who feel they do not have time to exercise on five days each week to consider finding time to commit to a lower weekly target of exercise. They also indicate the value of taking opportunities for short bouts of physical activity, which for those with time pressures from work or domestic life may be integrated into daily working routines," the report concludes.