How many extra years do you live with a healthy lifestyle?
Several large studies show that combining healthy habits delivers an average of two to four extra years of independent life after age 65 and lowers the risk of dying by 35 to 42%. Exercise is the most powerful single factor, but every healthy behaviour you add counts.
People who combine several healthy habits later in life gain an average of two to four extra years of independent living. This comes from a 13-year study following Chinese adults aged 65 and over. Those who had three or four healthy habits lived about 2.5 years longer independently compared with people who had hardly any healthy habits (slightly more for men, slightly less for women). Add favourable social circumstances to the mix, and the gain rises to almost four years for both men and women.
Of all the individual factors, being physically active makes the biggest difference. Among Chinese adults aged 60 and over, regular physical activity was linked to roughly 32% lower risk of dying. A healthy lifestyle as a whole, based on a combination of a healthy weight, not smoking, little alcohol, exercise and healthy eating, was linked to a 35% lower risk of death in people without long-term conditions, and even 42% lower in people who already had several conditions. In other words: the more you have to lose, the more you have to gain.
An analysis combining 35 studies involving more than 25,000 people aged 50 and over also showed that every individual healthy habit delivers measurable benefits. A Mediterranean diet lowered the risk of heart and blood vessel disease by around 22%. Sufficient exercise lowered the risk of becoming frail in later life by 33%. Sleeping seven to eight hours a night was linked to 25% less cognitive decline. Stopping smoking lowered the risk of heart and blood vessel disease by 32%. These studies did not report exact numbers of life years gained, but the effects on health outcomes are substantial.
Social stress works in the opposite direction. Higher social stress was linked to a 16 to 28% greater risk of dying among older Chinese adults. A healthy lifestyle softened this effect partly, but could not cancel it out entirely. Social support and lifestyle therefore reinforce each other: the combination delivers more than the sum of its parts.
This answer draws on several large studies in which people were followed for years, including a 13-year study among Chinese adults aged 65 and over and a study among Chinese adults aged 60 and over, as well as an analysis combining 35 studies involving more than 25,000 people aged 50 and over. The evidence points consistently in the same direction, but the precise numbers of life years gained were measured in specific populations (mainly in China) and cannot be translated one-to-one to other cultures or age groups. None of the studies can prove with certainty that lifestyle is the cause of longer life, although for most findings there is a sound biological explanation.