As if there isn’t enough evidence that exercise is good for you, researchers have found that poor physical fitness among middle-aged people is associated with smaller brain size 20 years later, according to a new study published in the online issue of Neurology.
“We found a direct correlation in our study between poor fitness and brain volume decades later, which indicates accelerated brain aging,” Boston University School of Medicine’s Nicole Spartano, lead author of the study, said in a press release. Researchers asked participants enrolled in the Framingham Heart Study, who were free from dementia and cardiovascular disease to exercise on a treadmill. On average, participants were 40 years old. Twenty years later, the researchers asked the same participants to take a second treadmill test and to submit MRI brain scans. They then excluded participants who had developed cardiovascular disease during the intervening decades.
The results? Researchers found that in the 1,094 participants who did not have heart disease, the ones who performed poorly in middle age – those who showed poor cardiovascular fitness, higher diastolic blood pressure and greater heart rate response – had smaller total brain volume two decades later. The smaller brain volume “was equivalent to approximately one additional year of brain aging. Because the study is observational, it shows an association between poor physical fitness and brain size, but does not prove that poor fitness causes a loss of brain volume.
The findings are significant because brain volume is important to healthy aging, says Dr. Ty Brown of St. Elizabeth Physicians Neurology. “Brain volume is important because a smaller brain means there have been neurons (brain cells) that have been lost. As you can imagine, the less brain tissue there is, the more difficulty there may be with various tasks.” That’s particularly true when it comes to memory, he says. “The more brain that is missing the more likely there is to be worsened memory problems.”
Brown cites a large body of research supporting the relationship between physical activity and brain health. He notes that numerous studies have shown exercise can help slow the process of neurodegenerative conditions, such as Alzheimer’s disease and Parkinson’s disease. Others have found that being active and healthy in midlife portends a better prognosis for avoiding the development of conditions such as Alzheimer’s disease later on in life. Still others demonstrate that among patients who already have dementia, the condition progresses more rapidly among inactive individuals than among those who exercise.
“I stress the importance of physical activity to my patients on a constant basis,” he says.
