Boston: Regular exercise is more important than genes if you want to live a longer life, according to new US research.

Risk factors such as smoking, diet and health account for three quarters of the variations in lifespan. Only one quarter is down to genes.

The research published in the Archives of the Internal Medicine Journal, studied a group of men aged 72 over a period of four years. A figure of 40 per cent lived to the age of 90 or more.

It was found that those who were overweight, with diabetes, hypertension and who smoked had a reduced life expectancy while those who reached 90 were in better physical shape.

A 70-year-old who does not smoke, has normal blood pressure and weight, without diabetes and who exercises two to four times a week has a 54% chance of living to 90.

The following all reduce life expectancy:

* Not taking exercise – cuts the chance of a man reaching his 90s to 44%
* Obesity – cuts the chances of reaching 90 to 36%
* Smoking to 22%
* High blood pressure to 26%
* A combination of factors such as no exercise, obesity and diabetes cuts it to 14%