Everyone’s brain shrinks as they get older — but there’s a way to lessen the effect. (Photo: Getty Images)
There are a lot of good reasons to stay physically fit into middle age. Better sleep, muscle strength, heart health, and even mental performance are all perks of keeping up with exercise. And now, a new study shows that staying in shape in your 40s might even help protect your brain from shrinking later on in life.
Researchers from the Boston University School of Medicine found an association between brain tissue volume at age 60 and physical fitness levels in a person’s 40s. Specifically, people in their 40s who had lower fitness levels or had a higher rise in diastolic blood pressure (the lower number in a blood pressure reading) or heart rate after spending a few minutes on a slower-moving treadmill (2.5 miles an hour) were more likely to have smaller brain tissue volume at age 60.
Researchers explained that when someone is not very physically fit, his or her blood pressure and heart rate will be much higher in response to just low levels of exercise, compared with someone who is physically fit.
"People with lower fitness levels tend to have higher blood pressure (upper arm) response to even lower-levels of exercise," study researcher Nicole L. Spartano, PhD, a postdoctoral fellow at the Boston University School of Medicine, tells Yahoo Health. "Therefore, during everyday activities, people with lower fitness levels may have higher blood pressure spikes throughout the day compared to people with higher fitness levels."
While researchers did not explore the exact mechanisms in the study, Spartano notes that research suggests “people with higher fitness levels have better oxygen delivery to the brain.”
"There are also many signaling mechanisms, initiated by engaging in exercise, that may explain these effects," she says. "Fitness is also associated with better artery health, which is known to play a role in brain health."
The study included 1,271 people who were part of the Framingham Offspring Study and underwent the treadmill testing at an average age of 41. Then, when they were 60, on average, they all underwent MRI brain scans and cognitive testing.
In addition to finding the association with brain tissue volume, the researchers found that people whose diastolic blood pressure increased more during the treadmill test did worse on the cognitive testing (which examined decision-making functioning) when they were 60. They also found an association between higher resting systolic blood pressure (the top number in a blood pressure reading) at age 40 and a greater volume of white matter hyperintensity, which they said is indicative of blood-flow loss that occurs with aging.
Related: 17 Ways To Age-Proof Your Brain
To be clear, everyone’s brain loses some volume with age. But the speed of brain atrophy is linked with cognitive decline, Spartano notes.
The study was presented at the American Heart Association EPI/Lifestyle 2015 meeting; because it has yet to be published in a peer-reviewed journal, the findings should be regarded as preliminary.
But still, this isn’t the first study to draw a correlation between physical fitness in middle age and brain health later in life. A study published last year in the journal Neurology showed that physical fitness in young adulthood (defined in the study as between ages 18 and 30) was associated with better performance on cognitive tests in the early- to mid-40s. Another study, also published last year, showed an association between being physically active and being less likely to develop dementia in elderly age.
Feeling inspired? Here are some tips for fitting a workout into your schedule.