We've known for decades exercise is a great anti-ager when it comes to how we look and how we function.
It keeps pot bellies at bay by burning kilojoules and fights frailty by building stronger muscles – but that’s just the tip of the iceberg.
It may also have the power to work deep down in our cells to slow biological ageing.
At Victoria's Federation University, molecular biologist Fadi Charchar is looking at how exercise affects the tiny caps, telomeres, on the end of DNA strands.
Often compared to the tags that protect the tips of shoelaces, telomeres do a similar job with our DNA – help protect our DNA from damage when they're in good shape.
When they start to fray and shrink as they can with the influence of age and bad habits like smoking, our DNA is more likely to deteriorate and increase our disease risk.
But in the past few years studies have found when people exercise regularly, especially moderate to intense aerobic exercise, their telomeres don't degrade as quickly, explained Professor Charchar, of the University's Faculty of Science and Technology.
"Now some studies show exercise can actually lengthen telomeres," he said.
Two years ago his own study of a small group of 40-ish ultra-marathon runners who typically ran 40 to 100 kilometres a week found, compared to sedentary people, the runners' telomeres were 11 per cent longer - knocking off something like 16 years from their biological ages.
He’s since repeated the study comparing athletes to sedentary people and again found that the athletes’ telomeres were longer.
Still, he said, you may not need to run marathons to do your telomeres a good turn - as The New York Times reported recently, US research into the exercise habits of 6500 people taking part in the National Health and Nutrition Examination Survey linked even modest physical activity with a 3 per cent lower risk of having very short telomeres but the odds improved dramatically in people who moved the most and who varied the kind of exercise they did - their risk of very short telomeres was almost 60 per cent lower.
Why does exercise have this effect?
We often assume that exercise improves our health by delivering more oxygen to our body, but in his research Fadi Charchar found the effect on telomeres was independent of oxygen uptake.
"We don't know the exact mechanism but we think it might be the effect of a gene called TERT which helps maintain and lengthen telomeres - our research has found exercise may enhance the function of TERT," he said.
"In addition, exercise causes changes in the DNA structure itself that can result in considerable benefits to cells that can be passed on to future generations in sperm cells."
But this link between exercise and longer telomeres is just part of the much bigger picture of epigenetics, the field of science that looks at how our lifestyle habits and environment can change how our genes behave in our body for good or bad, says Charchar.
There's been a lot of research into how our lifestyle influences health at a cellular level.
Still, there are many unanswered questions about exercise and telomeres - like what kind of exercise is optimal and how much should we do? So far, aerobic exercise is looking good, said Professor Charchar.
"We've just studied the effects of resistance training on telomeres and we found it helps a bit but not as much as aerobic exercise."
It’s no surprise that already there are anti-ageing supplements claiming to protect telomeres starting to make an appearance online, often with high price tags. But for now, the best – and cheapest bet – looks like a run or a walk in the park.
