Exercise is good for you. As rudimentary and simple as it may sound, a lot of the research done in the world of health, well-being, and fitness results in findings that support such a claim. Add the new study coming out of the Boston University School of Medicine to that list.

According to The Telegraph in the U.K., the new study has found a correlation between the pace a brain normally shrinks as people age and exercising done in their forties. Conversely, it also suggests that people with bad fitness levels throughout their thirties and forties were linked to increased brain shrinkage down the road.

“We found a direct correlation in our study between poor fitness and brain volume decades later, which indicates accelerated brain ageing,” said Dr. Nicole Spartano, the study’s lead author. “While not yet studied on a large scale, these results suggest that fitness in middle age may be particularly important for the many millions of people around the world who already have evidence of heart disease.”

In total, 1,583 people with an average age of 40 participated in the study that took place over the course of more than two decades. Participants were given a treadmill test that tracked their body’s maximum ability to utilize oxygen over one minute, or VO2 max as it’s known in fitness circles.

Two decades later they gave subjects the same test, analyzing the data to both include and exclude individuals who had developed conditions such as heart disease, and estimated overall exercise capacity by studying the total amount of time subjects were able to exercise before their heart rate reached a certain level.

The results found that brain volume shrunk at a rate equivalent to two years of accelerated brain aging for every eight units lower a person performed on the treadmill test two decades later.

It’s generally believed that exercise can help prevent and reduce the time spent being sick, which is important in itself considering Americans catch approximately one billion colds every year. The fact that there’s now more concrete evidence it can improve the health and functionality of your brain later in life only reinforces its importance.