Many people notice that staying physically active seems to help them think more clearly and remember things better as they age.
Doctors have long recommended exercise for heart health, weight control, and mood, but scientists have also suspected that it protects the brain.
Now, researchers at the University of California, San Francisco have uncovered a biological explanation for why exercise sharpens memory and thinking.
As we grow older, the brain becomes more vulnerable to damage. One important reason is the weakening of something called the blood-brain barrier. This barrier is a special system of tightly packed cells lining the blood vessels in the brain.
Its job is to act like a security guard, allowing helpful nutrients to enter while keeping harmful substances out. When we are young, this system works very well. But with age, the barrier can become fragile and leaky.
When the barrier weakens, harmful molecules from the bloodstream can enter brain tissue. This triggers inflammation, which damages brain cells and interferes with communication between them.
Inflammation has been strongly linked to memory loss, slower thinking, and diseases such as Alzheimer’s. Scientists have been trying to understand how to keep this barrier strong for many years.
Several years ago, the same research team discovered that exercise increased levels of a substance called GPLD1 in the liver of mice. Interestingly, animals with higher GPLD1 levels showed better brain function and appeared to resist age-related decline.
However, there was a mystery: GPLD1 cannot enter the brain, so scientists did not know how it could affect memory and thinking.
The new study has finally explained this puzzle. The researchers found that GPLD1 works indirectly by repairing the blood-brain barrier rather than acting directly on brain cells.
As animals age, another protein called TNAP builds up in the cells that form the barrier. Too much TNAP weakens these cells and makes the barrier more permeable, allowing harmful substances to pass through.
When mice exercised, their livers released more GPLD1 into the bloodstream. This enzyme traveled through the body and removed excess TNAP from the barrier cells surrounding the brain. By clearing away this damaging buildup, GPLD1 helped restore the barrier’s strength and prevented inflammation from entering the brain.
To confirm TNAP’s role, scientists conducted additional experiments. Young mice engineered to produce too much TNAP developed memory problems similar to those seen in older animals.
In contrast, when researchers reduced TNAP levels in elderly mice, the barrier became stronger, inflammation decreased, and the animals performed better on memory tests. Remarkably, these improvements occurred even late in life, suggesting that brain aging may be more reversible than previously believed.
The findings are important because they reveal that brain health is closely connected to the rest of the body. Exercise does not just strengthen muscles and the heart; it also triggers protective processes in the liver and blood vessels that benefit the brain.
This discovery opens the possibility of developing new treatments that mimic the effects of exercise, especially for people who are unable to stay physically active due to illness or disability.
In analyzing the study, the results suggest a promising new direction for preventing cognitive decline and Alzheimer’s disease. Instead of focusing only on the brain, future therapies might aim to protect the blood-brain barrier or regulate proteins like TNAP.
However, it is important to note that the research was conducted in mice, and more studies will be needed to confirm whether the same mechanism works in humans.
Overall, the study provides strong evidence that regular physical activity may help preserve memory and thinking by protecting the brain’s natural defense system. It reinforces the idea that healthy aging depends on caring for the entire body, not just the brain alone.
While scientists continue to explore new treatments, one simple message is already clear: staying active may be one of the most powerful ways to keep the mind sharp later in life.
If you care about Alzheimer’s, please read studies about Vitamin D deficiency linked to Alzheimer’s, vascular dementia, and Oral cannabis extract may help reduce Alzheimer’s symptoms.
For more information about brain health, please see recent studies about Vitamin B9 deficiency linked to higher dementia risk, and results showing flavonoid-rich foods could improve survival in Parkinson’s disease.
The study is published in Cell.
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