A new study has found that staying aerobically fit, especially through middle age and beyond, can delay biological aging by up to 12 years and prolong independence during old age.
Aerobic exercise, such as jogging, swimming, cycling or walking - improves a person's oxygen consumption and boosts their metabolism.
But maximal aerobic power starts to fall steadily from middle age, decreasing by around 5 ml/[kg.min] every decade.
When it falls below around 18 ml in men and 15 ml in women, it becomes difficult to do very much at all without severe fatigue.
In a typical sedentary man, the maximal aerobic power will have fallen to around 25 mil/[kg.min] by the age of 60, almost half of what it was at the age of 20.
But the evidence shows that regular aerobic exercise can slow or reverse the inexorable decline, even in later life.
Research by scientists at the University of Toronto in Canada has shown that high-intensity exercise, taken regularly for more than a year, can boost maximal aerobic power by 25 percent, equivalent to a gain of 6 ml/ [kg.min], or 10 to 12 biological years.
"There seems good evidence that the conservation of maximal oxygen intake increases the likelihood that the healthy elderly person will retain functional independence," an author said.
The other positive spin-offs of aerobic exercise are reduced risks of serious disease, faster recovery after injury or illness, and reduced risks of falls because of the maintenance of muscle power, balance, and coordination.
The results are published in the British Journal of Sports Medicine.