Sixty declared the new middle-age as we live longer and healthier lives
People may need to rethink what they believe is old as researchers have suggested that 60 is the new middle-age.
The claim is made by Dr Sergei Scherbov, the world population programme deputy director at the International Institute for Applied Systems Analysis in Austria, who worked on a study of future population projections.
The study, led by Prof Warren Sanderson of Stony Brook University in New York, notes that if old age is fixed at a certain point, the proportion of old people will rise because of increasing life expectancy.
If the threshold for being old is moved to take into account longer lives, the proportion of old people falls over time.
"What we think of as old has changed, and it will need to continue changing in the future as people live longer, healthier lives," Dr Scherbov said. "Someone who is 60 today, I would argue is middle-aged. Say, 200 years ago, a 60-year-old would be a very old person."
With people living longer, healthier lives, age should not be simply a number we reach but a reflection of the life we lead, according to the study.
Researchers compared the proportion of the population that was categorised as "old" using the conventional measure that assumes that people become "old" at 65, and the proportion based on their new measure of age.
"The onset of old age is important because it is often used as an indicator of increased disability and dependence and decreased labour force participation," said Prof Sanderson.
"Adjusting what we consider to be the onset of old age when we study different countries and time periods is crucial for the scientific understanding of population ageing for the formulation of policies consistent with our current demographic situation."
Lisa Harris, the head of communications at Saga, claimed that "middle-age is most certainly a state of mind".
"We are living longer, healthier lives and the face of later life is changing beyond all recognition," she said.
"Retirement is no longer a cliff-edge decision where we stop working purely because we've celebrated a birthday.
"Instead, we change the way we work, often with the goal of achieving a more rewarding work-life balance that allows us to feel valued in the workforce for the experience we offer.
"It also lets us travel, take part in hobbies and generally have a bit of fun too."