Three 30-minute strolls each week can help lower blood pressure and thus reduce cardiovascular risk.
Experts recommend that adults do 'moderately intense' exercise five times per week but a new Irish study suggests even light exercise provides similar health benefits.
The study involved 106 healthy but sedentary civil servants between the ages of 40 and 60 who took part in an exercise programme over 12 weeks.
One group walked briskly for 30 minutes five times a week; a second group did the same thrice weekly, while the remainder were told not to change their current regime.
Blood pressure, blood cholesterol, weight, hip and waist girth, and overall fitness were measured at the start and finish of the study by researchers from Queen's University, Belfast.
The results revealed significant falls in systolic blood pressure and waist and hip girth in both groups of walkers.
However, the authors said people should still aim to exercise five times each week as the study showed that activity below the recommended weekly levels still makes a difference to health.