From the linked article:
In the new study, which was published this week in The Journal of Physiology, scientists at King’s College London and the University of Birmingham in England decided to use a different approach. They removed inactivity as a factor in their study of aging by looking at the health of older people who move quite a bit. “We wanted to understand what happens to the functioning of our bodies as we get older if we take the best-case scenario,” said Stephen Harridge, senior author of the study and director of the Centre of Human and Aerospace Physiological Sciences at King’s College London.
To accomplish that goal, the scientists recruited 85 men and 41 women aged between 55 and 79 who bicycle regularly. The volunteers were all serious recreational riders but not competitive athletes. The men had to be able to ride at least 62 miles in six and a half hours and the women 37 miles in five and a half hours, benchmarks typical of a high degree of fitness in older people.
As it turned out, the cyclists did not show their age. On almost all measures, their physical functioning remained fairly stable across the decades and was much closer to that of young adults than of people their age. As a group, even the oldest cyclists had younger people’s levels of balance, reflexes, metabolic health and memory ability.
Read the article; it's not all as simple as that, and, of course, the results don't last forever. My favorite part is the description of "serious recreational riders": men who have to average 9.5 mph, and women who have to average less that 6.75 mph. TEW doesn't like to ride more than about 25 miles, but she could do 25, come home, take a nap, and get up and still finish the rest in the allotted time.
I also like the chainring tattoo in the pic (it's from the article).