Men and women who start running competitively when they are in their 50s can be as swift, lean and well-muscled within a decade as competitive runners who have trained lifelong.

These are the findings of a study that suggests that middle age is not too late to take up intense exercise training and begin banking many of the health and aging benefits of being an athlete.

There’s a wealth of research that indicates that older athletes — known as masters — age differently than older people who are sedentary. Past studies show that competitive athletes in their 60s, 70s, 80s and even 90s tend to have more and healthier muscle mass, stronger hearts and much less body fat than non-athletes of the same age.

In essence, masters athletes represent “the model of healthy aging,” said Jamie McPhee, a professor of musculoskeletal physiology at Manchester Metropolitan University in England, who led the new study.

But past studies have looked at participants, mostly men, who have trained for decades. No one had looked into whether people who start training in midlife can catch up to longer-term competitors’ performance and health.

For more than a decade, McPhee and his colleagues had been studying the muscle and bone health of older athletes who had been running for decades. For the new study, which was published in Frontiers in Physiology, they decided to look into whether it mattered when athletes started training.

The scientists gathered records for 150 masters runners and divided them into two groups. One group, the early starters, had been racing for decades, some since they were teenagers. The latecomers had not begun training and racing until they were at least 50. While both groups included men and women, the latecomers featured a much larger percentage of women, reflecting their growing interest in running in recent decades.

The researchers also gathered data about the body compositions of 59 inactive older men and women from a separate, long-term study of health and aging to provide a control group.

When they compared the health and performance parameters of the runners in each group to one another, they were surprisingly similar. Their race finishing times barely differed. Both groups of runners also showed about 12% greater muscle mass in their legs than the inactive control group and about 17% less body fat.

Only with bone density were the latecomer runners at a disadvantage. Their spinal bone density tended to be lower than the long-term runners. The reason isn’t clear, McPhee said, although it could relate to the difference in the groups’ gender makeup.

The upshot is that it does seem to be “possible to catch up with those who have trained several decades longer,” McPhee said.

There are caveats, though. This study did not look at markers of health apart from muscles and bones. It also did not delve into participants’ genetics or their physiques before they joined the study, either of which could have uniquely fitted them to become older athletes and might not apply to the rest of us.

But even with these provisos, the study’s findings are encouraging, McPhee said, suggesting that, whatever our age, it may not be too late for us to become healthier and, if we so choose, even late-blooming athletes.