Pensioners who spend just half an hour a day pottering in the garden, fishing or walking can reduce fatal heart attacks by more than half. Research on 2,500 men and women aged between 65 and 74, found that those with an active retirement had far lower death rates. Until now, much of the evidence about the benefits of exercise in protecting the heart has come from studies on those who are young or middle-aged.But the new study suggests dramatic changes could be achieved later in life.Researchers compared three groups of pensioners, depending on whether they reported low, medium or high levels of activity.Participants were classed as having low levels of activity if they did less than four hours' physical activity each week.They were compared to a group who were moderately active - taking light forms of exercise such as gardening, fishing, walking or cycling - for at least four hours a week.They were tracked against a third group of high-intensity exercisers - these did running, swimming, ball games or intense sports competitions for at least three hours a week.Moderate physical activity for at least four hours a week was associated with a 54% reduction in deaths from heart conditions, with a 31% drop in acute events such as heart attacks and strokes. Those in the group that did even more vigorous activity did still better, with a 66% reduction in heart deaths and a 45% drop in acute events. ..