Healthy habits like not smoking and staying physically active helps even after age 75, a Swedish study suggests.

Living a healthy lifestyle can add five years to women’s lives and six years to men’s, researchers report in Thursday's issue of the British Medical Journal.

The average age at death of those who regularly swam, walked or did gymnastics was two years greater than those who did not. (Juan Carlos Ulate/Reuters)

Smoking, alcohol consumption and being underweight or overweight are known to predict mortality among the elderly, but it wasn't clear if that applied to the oldest people aged 85 and older.

To investigate, Debora Rizzuto of the Aging Research Center at Stockholm University and her co-authors followed more than 1,000 Swedes aged 75 and older for 18 years who lived at home and in institutions. Nurses interviewed them about their age, sex, occupation, diet and lifestyle activities when the study began.

During the course of the study, 92 per cent of participants died.

"Even among those aged 85 years or more, the median age at death could be four years higher if the participants had a healthy lifestyle, a rich or moderate social network, and engaged in at least one leisure activity," the study’s authors concluded.

Staying social

The richness of a social network was defined as being married or living with someone, having children with whom they were in daily to weekly contact that was satisfactory and having relatives or friends with that same level of contact.

"Our results suggest that encouraging favourable lifestyle behaviours even at advanced ages may enhance lifestyle expectancy, probably by reducing morbidity."

Smokers died one year earlier than non-smokers, the researchers found.

Leisure activities ranged from reading, doing crossword puzzles, swimming, attending concerts to gardening. Of these, physical activity was most strongly associated with survival. The average age at death of those who regularly swam, walked or did gymnastics was two years greater than those who did not.

The researchers acknowledged that they adjusted for many factors that could be associated with longevity but they couldn't consider everything, such as quality of diet. The drop out rate at the start of the project was also nearly 24 per cent.

Funding for the study included the Swedish Council for Working Life and Social Research, Swedish Council for Medicine, Swedish Brain Power and Karolinksa Institute.