Low-intensity exercise like walking for a minute at a time can cut blood pressure and even housework and gardening chores can add years to your life.
The breakthrough comes after tests showed it is better to keep moving throughout the day rather than undertake an intense burst of exercise followed by rest.
The results from a study of more than 1,000 elderly people published in the Journal of the American Heart Association are the clearest sign yet that exercise taken little and often, and a healthy diet, are the key to a long and healthy life.
Lead researcher Dr Thomas Buford, of the University of Florida Institute on Ageing, found that elderly people with limited mobility can lower their risk of heart attack and coronary death by a minute of physical activity.
Dr Buford said: “In the past, much of the emphasis was placed on engaging in structured physical exercise.
“It is becoming increasingly evident, however, that encouraging individuals to just reduce the amount of time they spend being sedentary may have important cardiovascular benefits.”