One needs only to step out the door and go for a run to reap the benefits of exercise -- you finish refreshed, more alert and with a sense of accomplishment. A study published this week in the British Journal of Sports Medicine reminds us that that effort will pay off in the future as well, not just with added years, but with healthy ones.

In the study, researchers in Australia assessed the physical activity level and the physical and mental health of 12,200 men ages 65 to 83. Ten to 13 years later, subjects who were still alive were assessed again.

Plus: Runners Have Lower Risk of Dying from Respiratory Disease

The analysis showed that the men who exercised at least 2.5 hours per week were more likely to be alive 10 years later. And after adjusting for lifestyle and disease (i.e., age, marital status, body mass index, smoking, alcohol use and the prevalence of heart disease), active subjects were more likely than their inactive peers to enjoy those years free of mental and physical ailments, including depression.

In other words, exercise helps keep our faculties intact as we age -- if we keep at it. Men who began the study as active seniors but stopped exercising lost many of the health benefits associated with exercise. Subject who continued to accumulate at least 2.5 hours of weekly activity were 60 percent more likely to age healthfully. Moreover, men who started exercising during the study increased their chance of healthy aging by 35 percent.

Related: Masters Athletes Have Superior Brain Function

"We found that the health benefits of physical activity appeared to be all but lost among active men who became inactive over the following decade, whereas men who were physically inactive and became active accrued the benefits of healthy aging. Taken together, these results support the hypothesis that physical activity promotes healthy aging," the authors write.

The research follows on the heels of another study that shows that it’s better to be a fit senior than an unfit one: That research found that active older adults were less prone to distraction than their inactive peers.

Source: British Journal of Sports Medicine