Once people reach a certain age, their "will to live" is a strong predictor for survival irrespective of their age, gender or whether they suffer from two or more chronic, life-affecting illnesses.
Experts now believe the key to living longer may simply lie in maintaining a good outlook, boosting feelings of optimism and life satisfaction.
Scientists from Helsinki University looked at 400 people aged between 75 and 90 who lived independently in the city.
They wanted to assess the people's will to live which -- although it is highly subjective -- can be defined as a psychological expression of the striving for life.
"Put simply, our study showed that those who wanted to live longer also survived longer," lead study author Helena Karppinen was quoted as saying by the Daily Express.
The study is published in the British Geriatrics Society journal of Age and Ageing.