Most Kiwis biologically 2 years older than their age

NZ Warriors and former All Blacks doctor John Mayhew said the research marked a national "line in the sand". Photo / Getty Images

New research shows our stressful lifestyles are ageing us beyond our years.

Whether it's work pressure, financial stress or spending too much time looking after the needs of others, our own health is coming second.

A study, commissioned by insurance company Sovereign, shows at the extreme end, our lifestyle and stress can even add 20 "penalty years" of age.

Penalty years are added through a "health age generator" that assesses everything from exercise to sleep patterns and drinking habits.

So, a 40-year-old with five penalty years, has effectively aged themselves into a 45-year-old.

Overall, the generator revealed that in the 1200 Kiwis surveyed, there was a national average of two penalty years.

Men fared better than women, averaging 1.2 penalty years against 2.2, while penalty years decreased in older Kiwis.

NZ Warriors and former All Blacks doctor John Mayhew said the research marked a national "line in the sand".

"The main factors seen to be impacting the health age average are work, stress, risky behaviour -- like unsafe driving or poor sunsmart choices -- and alcohol consumption," said Dr Mayhew, who is Sovereign's chief medical officer.