BOSTON, Feb. 15 (UPI) -- People who exercise during middle age maintain the size of their brains as they age, researchers report in a long-term study.
Researchers at Boston University found people who were less active in their 40s were had smaller brain volumes, though researchers caution the study does not prove that poor physical fitness causes a loss of brain volume.
The association was linked to heart health and blood pressure, researchers said, because of the importance of proper oxygenation of the brain and how much blood reaches it. Physical activity can maintain proper health of both, which helps the brain.
Previous research has shown exercise can prevent brain aging, leading researchers to investigate the effects of exercise on brain size over the course of several decades.
"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," Dr. Nicole Spartano, a researcher at the Boston University School of Medicine, said in a press release.
For the study, published in the journal Neurology, researchers studied treadmill tests from 1,583 participants in the Framingham Heart Study with an average age of 40 who did not have dementia or heart disease. Each participant took a treadmill test and an MRI of their brain at the beginning of the study, and took another treadmill test and MRI an average of 18 years later.
Based on measurements of oxygen used during treadmill tests, as well as blood pressure and heart rate tests, people who were more active in their 40s tended to have larger brain volumes later. When researchers removed participants who developed heart disease or started taking beta blockers for blood pressure, leaving 1,094 participants, more active people still had larger brain volumes.
"Over the course of a lifetime, improved blood flow may have an impact on brain aging and prevent cognitive decline in older age," Spartano told CNN. "The broad message is that health and lifestyle choices that you make throughout your life may have consequences many years later."