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Do you need one more reason to sit less, exercise more, and get in shape? If so, scientific evidence is mounting that aerobic activity and cardiovascular fitness can increase brain volume throughout your lifespan. On the flip side, a new study has found that a lack of physical activity and being out of shape in midlife may cause your brain to shrink as you age.
Recently, researchers in Finland published a study confirming that sustained aerobic activity stimulates the birth of new neurons (neurogenesis) in the adult hippocampus which increases brain volume. Another study from Boston University has identified that poor physical fitness in middle age is associated with smaller brain size decades later.
The February 2016 study, “Midlife Exercise Blood Pressure, Heart Rate, and Fitness Relate to Brain Volume 2 Decades Later,” was published online in the Journal of the American Academy of Neurology. According to the researchers, the goal of this study was, “to determine whether poor cardiovascular fitness and exaggerated exercise blood pressure and heart rate were associated with worse brain morphology in later life.”
The Boston University study consisted of 1,583 people who were initially enrolled in the Framingham Heart Study two decades ago. In the mid-90s, all of the participants in this study took an exercise treadmill test that measured their physical fitness. At the time of the initial study, the average participant was forty years old. Two decades later, when the average participant was 60-years-old, participants took the treadmill test again—but this time they also had a state-of-the-art MRI brain scan.
During both treadmill tests, exercise capacity was estimated based on the amount of time a participant was able to exercise comfortably before his or her heart rate hit a certain level. Throughout the fitness tests, the researchers measured each person's VO2, which is the maximum amount of oxygen the body is able to metabolize in one minute. Oxygen consumption during physical exercise reflects aerobic fitness and is the most common way to determine someone's physical endurance during aerobic activity
The more out of shape someone had been in the 1990s was directly correlated with smaller brain volumes two decades later. In fact, for every eight units of lower VO2 performance the researchers identified a reduction of cerebral brain volume equal to one year of accelerated brain aging.
This study also found that people whose blood pressure and heart rate went up at a higher rate during the treadmill test were also more likely to have smaller brain volumes two decades later.
Physical Fitness Is Paramount for Maintaining Brain Health As You Age
The researchers of the latest study conclude that poor cardiovascular fitness, higher blood pressure, and increased heart rate in response to exercise at baseline were associated with a smaller brain volume almost two decades later.
In a press release, study author Nicole Spartano, Ph.D., with Boston University School of Medicine, said, "We found a direct correlation in our study between poor fitness and brain volume decades later, which indicates accelerated brain aging." Spartano noted that people with poor physical fitness often have higher blood pressure and heart rate responses to low levels of exercise compared to people with better fitness.
There is one important caveat. As a classic example of causation vs. correlation, this study has identified a correlation between lower brain volume and a lack of physical fitness; the study does not categorically prove that poor physical fitness causes a loss of brain volume. That said, there is growing evidence that physical exercise and cardiorespiratory fitness have the power to optimize brain structure and functional connectivity of both gray and white matter in the brain throughout a person's lifespan.
Conclusion: Epidemic Sedentarism May Be Causing Our Brains to Atrophy
In a digital era, sedentarism has become an epidemic. Therefore, to maintain a healthy mind in a healthy body, each of us must consistently make a committed effort to sit less and move our bodies more. It's estimated that the average American spends 13 waking hours sitting. How many hours do you spend sitting every day?
Ironically, as I sit at my laptop typing this blog post now. . . I can attest to the growing amount of time that the average American spends sitting every day. I know from first-hand experience that staying in shape and not sitting for copious amounts of time most days of the week takes much more vigilance than it did a decade ago.
Unfortunately, the recent influx of digital devices and the dramatic increase in daily screen time means that most of us spend more time sitting than ever before in our evolutionary history. Our bodies have not evolved to spend the majority of the day sitting, or being perpetually glued to a digital screen in a sedentary position.
Hopefully, these findings on brain volume will energize and motivate you to: sit less, stay physically active, and maintain your aerobic fitness at every stage of life. Physical activity is proving to be a fundamental ingredient for maintaining a healthy mind, brain, and body throughout the human lifespan.
To read more on this topic, check out my Psychology Today blog posts,
- "More Proof That Aerobic Exercise Can Make Your Brain Bigger"
- "Physical Activity Is the No. 1 Way to Keep Your Brain Young"
- "Sitting Can Drain Brain Power and Stifle Creativity"
- "Hippocrates Was Right: "Walking Is the Best Medicine""
- "Why Does Physical Activity Improve Cognitive Flexibility?"
- "The Brain Drain of Physical Inactivity"
- "Scientists Discover Why Exercise Makes Your Smarter"
- "Making Exercise a Habit Can Prevent Age Related 'Brain Drain'"
- "Irisin: The “Exercise Hormone” has Powerful Health Benefits"
- "Is Excessive Screen Time Slowly Undermining Our Resilience?"
- "Face-to-Face Contact Reduces Risk of Depression"
© 2016 Christopher Bergland. All rights reserved.
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