For this report, Bancks and his colleagues reviewed data on 518 people participating in a long-range heart health study.
The participants, now an average age of 51, had been followed for three decades. They have received follow-up exams every two to five years, and had brain scans 25 years after entering the study, the researchers said in background information.
The research team rated each participant based on how well they followed each of Life's Simple 7 at the start of the study. A person received scores between zero and 2 points for each recommendation, depending on how closely they followed it, with a maximum heart healthy score of 14.
Researchers then compared those scores against the brain scans performed in middle age, to see whether living healthy as a young adult mattered years later.
As it turned out, each 1-point improvement in a young person's heart-healthy lifestyle score was "essentially the same as one year less in brain aging," Bancks said. "As the score increases, you see a better result for brain structure."
However, not all the heart association's recommendations carried the same weight. Smoking had a stronger association with smaller brain volume than the other lifestyle factors, the researchers found.
The brain is highly dependent on a healthy heart and circulatory system to work right, so it makes sense that heart-healthy living would result in a healthier brain, Bancks said.
"The brain is supplied by this rich network of blood vessels, which provides the oxygen- and nutrient-rich blood it needs to function normally," Bancks said. "A healthy heart helps ensure enough blood is pumped through these blood vessels, and healthy blood vessels help ensure that network is intact to supply the entire brain with nutrients and oxygen."
This doesn't mean that you should give up if you haven't paid attention to your heart health until your 40s, Baltan added.
"This isn't putting us in a hopeless situation," Baltan said. "It's another alert that we can start at an even earlier age to maintain our brain health."
The new study appears July 19 in Neurology.