The key is to do moderate-to-high levels of exercise, the sort that leaves you a little out of breath. This idea was tested on heart patients aged 50 or over, and their results were compared with those of healthy volunteers.
For men, life expectancy increased by up to 3.7 years among those with heart disease, compared with an improved life expectancy of up to 3.2 years among the healthy volunteers. The figures for women were up to 3.5 more years in the heart-disease group and up to 3.3 more years in the healthy volunteers.
Those who maintained low levels of physical activity saw little or no improvement in their life expectancy (Arch Intern Med, 2005; 165: 2355-60).