If you’re worried about your body slowing down and losing your balance, reflexes, memory, and metabolism as you get older, rejoice.

There’s something you can do to prevent or at least hold off this seemingly inevitable human decline, according to a new study.

It’s all about exercise.

On many measures, active older adults can perform just as well as people decades younger.

We already know that exercising improves health, sleep, mood, and more. But in this latest study, published in The Journal of Physiology, researchers wanted to see how exercise affected aging in a group of highly active older adults. They looked at 84 men and 41 women aged between 55 and 79.

Researchers chose highly active healthy participants with similar lifestyles to try and control for lifestyle factors that may affect how people age (it’s harder to control for genetic differences, though the researchers note that exercise helps prevent genetic damage in the first place).

Then they took a look at the physical profiles of their group — all were serious recreational cyclists, though not competitive athletes. They chose cyclists because bicycling is balance-intensive, and it requires and builds physical strength without putting too much stress on joints.

They looked at the group’s cardiovascular systems, lung health, neuromuscular structure, metabolism, hormone levels, mental functions, bone strength, and general health. The question was if or how the group’s age would show in these measures.

The results were surprising.

“If you gave this dataset to a clinician and asked him to predict the age” of any one of these individuals based on these test results, Dr. Stephen Harridge, senior author of the study, told the New York Times, “it would be impossible.”

Age did have an impact on a couple of measures. The oldest members of the group had less muscle mass and less endurance than the younger ones. Even there, though, they were much closer to younger people than to people their own age.

But as for those other measures, including tests of balance, cognitive agility, reflex, and metabolism, Harridge told the Times that it seems “being physically active makes your body function on the inside more like a young person’s.”

They also noted that the group scored better on measures of mental health, including anxiety and depression, possibly due to the benefits of exercise.

It’s worth noting that the group studied is a small sample size, and researchers want to confirm these results with more and different groups of people. Also, these participants were all cyclists who had stayed active and healthy for many years, which could influence results as well — and perhaps there’s something particularly effective about cycling. More research is needed on all those questions.

But these results are still promising, and the researchers say that they’ll follow up with this group in five and 10 years to see how things have changed.

Still, they think this provides important evidence that staying active is crucial to healthy aging.