The world's most pre-eminent ageing experts - and some of Australia's oldest citizens - are meeting to unravel the secrets to a long life.
Can humans live to the age of 150? Is it even desirable?
These are the questions being debated among some of the world's most pre-eminent experts - and some of Australia's oldest citizens - at the second international 'Living to 100' conference hosted by the Centre for Healthy Brain Ageing (CHeBA) in Sydney this weekend.
Professor Peter Schofield is the CEO of Neuroscience Research Australia (NeuRA) and has been studying the brain for decades.
He believes it is plausible that humans may one day reach the age of 150.
"The things that may make it possible to conceive that humans will live to 150 are probably going to have to be quite innovative - they are probably going to need things like potential genetic therapies, drug therapies," he told SBS News on Saturday.
But Professor of Neuropsychiatry at UNSW, Perminder Sachdev is not so optimistic, even if some animal studies have shown life can be prolonged using diet, genetic manipulation and drugs.
"I think that in humans this is going to be much more complex," said Professor Sachdev.
"We know that in the last several thousand years the maximum human lifespan has not really increased very much and even the last 30 to 40 years, there have been many medical advances and we know that more and more people are living into their 80s and 90s - and also over 100 - but the maximum lifespan has not increased," said Professor Sachdev.
"So I'm not really optimistic that we're going to make a massive change to the maximum human lifespan," he said.
However, more people reaching an older age in a healthier state is possible, according to Professor Sachdev.
"We want to increase the maximum healthspan more so than the maximum lifespan," added Professor Sachdev.
"Living healthier for a longer period of time is really the holy grail I think," he said
In 2012, there was a little more than 420 thousand people aged 85 and above in Australia.
According to the Australian Bureau of Statistics' upper projections, that will more than double in the two decades to 2031.
Then double again by 2045. And again by 2069.
Personality could be key to a longer life
What the experts do agree on is that there common lifestyle factors that are key to becoming a centenarian aside from a person's genetics.
These include good nutrition including no processed food, physical activity and staying socially engaged.
"What we're realising is these common factors relate not just to genetics but also the lifestyle of individuals," said Professor Sachdev.
"We're also discovering there may be some personality factors that may be very important to achieve very old, well lived successful age," he added.
Personality traits linked to living longer are conscientiousness and optimism, according to Professor Sachdev.
"We see these people at the age of 90 or 95 and even 100 participating in social activities, they're making a positive contribution to others and overall they have a lower level of anxiety, a lower level of what we call neuroticism, they do not react to stimuli in an excessive manner, and they seem to handle stress in a more resilient fashion; they seem to bounce back from many stresses they experience through life."
What do the centenarians say?
For Eileen Kramer, 103, dancing has been the key to her longevity.
"I dance, I dance through life," said Ms Kramer.
Tom Sample, who was raised in the NSW city of Newcastle and lived in Warragamba in western Sydney for many years, is yet to reach the age of 100 but is close.
At the age of 97, he credits a loving marriage and sport for his long life.
"I was married for 66 years, I lost my wife about three years ago," Mr Sample said.
"Being such a loving couple it helped in my long life which I am now enjoying," he said.