Researchers tracked the health of 3,454 people in England with an average age of 64 living in the community.
They defined healthy aging as being free of major chronic ailments such as heart disease or stroke, diabetes, emphysema, or Alzheimer's disease as well as having good mental health, preserving cognitive abilities, and being able to maintain social connections or activities over the eight years of followup.
"We demonstrate, for the first time, that participants who remained physically active through followup were most likely to age successfully," Simon Bacon of the Montreal Heart Institute at Concordia University and his co-authors concluded in the British journal of Sports Medicine.
"This study supports public health initiatives designed to engage older adults in physical activity, even those who are of advanced age."
Participants who took up activity were also more likely to remain healthy compared with those who continued to be inactive.
The findings show it's never too late to get fit and enjoy its benefits beyond the physical, Bacon said.
For older adults, barriers to physical activity may include not feeling safe or comfortable hitting the gym, he said.
In the study, participants described the frequency and intensity of their physical activity in 2002-03, and then every two years until 2010-11. Some participants also had objective measurements of their physical activity.
The subjects also had their cognitive abilities and mental health assessed with a battery of tests, such as immediate and delayed recall of a list of 10 words and an objective test of walking speed.
Over the four years, nearly nine per cent became active, 70 per cent continued to get moderate or vigorous activity at least once a week, and nearly 12 per cent became inactive. The Public Health Agency of Canada lists walking quickly or bike riding as moderate-intensity aerobic activity and jogging or cross-country skiing as vigorous.
At eight years, participants who reported moderate activity were 3.1 times more likely to be healthy agers and those who took part in vigorous activity were 4.3 times more likely to be healthy agers compared with inactive participants.
The researchers acknowledged that a controlled trial is needed to test for cause-and-effect but said the long-term nature of the study of seniors living in the community offers better representation.
They took factors such as age, sex, smoking, alcohol intake, marital status and wealth into account in their statistical analysis. Those who had a disease when the study began were excluded.
The study was funded by National Institute on Aging in the U.S. and a consortium of U.K. government departments.