Over the last decades, research has proven that aging isn’t just about our years in birthdays. Instead, we may be better served by knowing how organs and cells have handled those years. This powerful science helps explain why two people of the same age could have vastly different risks for age-related issues like frailty, heart disease, and early death. Fundamental to this work is the understanding that different parts of our bodies age at different rates. Now, this research is being applied to the brain, and a new set of data is demonstrating that one simple test provides deep insights into how fast your brain is aging.
It’s been well-known that certain metrics of functional health tend to drop off as we age.
In a 2019 study published in JAMA Network Open, researchers followed over 900 people for about 40 years, tracking their brain function, physical function, blood markers, and adult brain structure to look at correlations between aging and brain function. Among the results, the authors of this study noted a significant correlation between walking speed at age 45 and markers of brain aging.
To explore the links between walking speed and the brain, a host of metrics were tested. First, researchers found that slower walkers tended to have a smaller brain volume. Next, they found increased white matter hyperintensities (a brain imaging marker associated with cognitive decline). Additionally, they noted thinning of the brain’s cortex as well as a reduction in the total surface area of the cortex. Finally, slower walking was linked to a greater decline in cognitive abilities from childhood to adulthood. Of particular note was that a slower walking speed also correlated with a more rapid speed of aging as measured by a 19-biomarker panel.
How fast did they go? The slowest group walked an average of 2.71 miles per hour (1.21 m/s) across several walk tests, while the fastest group clocked in at 3.91 mph (1.75 m/s).
The results of this study point to a clear signal: walking slowly in midlife is linked to faster aging and worse brain health. But a correlation doesn’t necessarily imply causation. It’s also possible that faster aging and certain brain states predispose to slower walking, and there was some evidence from this study that certain outcomes were significantly influenced by brain and body measurements in childhood. This is why it’s important to note additional data supporting walking to improve brain health. In one randomized trial published in the Proceedings of the National Academy of Sciences, 60 older adults were allocated to a walking or stretching group for a year. Remarkably, the walking group showed an increase in the size of the brain’s memory center, the hippocampus, by 2 percent, while the stretching group showed shrinkage. In another smaller study in diabetics, walkers demonstrated a variety of cognitive benefits over a control group. This type of finding is supported by the massive amount of literature showing that exercise positively influences key systems involved in brain health, including immunity, metabolism, and neuroplasticity.
The bottom line: Our ability to move is tethered to longevity, and especially brain longevity. In our modern sedentary lives, any motion is wonderful. Walking can sometimes seem less impressive, but it’s an easy way to help protect overall and brain health. Getting in more daily steps through short walks, or even an under-desk treadmill, can help offset aspects of our often-seated jobs.