Exercise may help the aging brain “take out the trash”

VU researcher Dr. James Broatch led the analysis, which examined how exercise may influence the glymphatic system, a brain waste clearance pathway that is especially active during sleep. This system helps maintain and regulate brain health, and its role becomes increasingly important with age.

How Exercise May Support the Aging Brain

The benefits of exercise for healthy aging are already well established, but researchers are still working to understand exactly how physical activity protects the brain. Finding those mechanisms is particularly important because more than 10 million people worldwide are diagnosed with dementia each year, and there is currently no cure.

The peer-reviewed paper, "Exercise as a regulator of glymphatic function," was recently published in the journal Trends in Neurosciences. Researchers reviewed existing studies of the glymphatic system in both animals and humans.

Although more research is still needed (some of which Dr. Broatch is currently undertaking), the analysis found that exercise can improve several physiological processes involved in regulating glymphatic function.

These benefits include reducing blood pressure and vascular stiffness, improving the activation of neurons in the brain, reducing inflammation in the brain, lowering resting norepinephrine, and improving sleep. Exercise may also increase the quality of deep sleep and enhance slow wave activity associated with brain waste clearance.

Helping the Brain Clear Away Daily Waste

Dr. Broatch said the connection between exercise and brain protection could provide an important clue as scientists search for evidence-based forms of physical activity that may help limit brain deterioration with age.

"If we don't have opportunities for the brain to essentially clean out the junk from the day, we know that build-up is damaging, especially as we age. Sleep is more crucial than ever to play this role, but the irony is, good quality sleep can often be harder to get as we get older. This study asked, what if exercise could support that process?" Dr. Broatch said.

Because the glymphatic system performs much of its cleanup work during sleep, exercise could potentially support brain health through several connected pathways. The findings point to better sleep, healthier blood vessels, reduced inflammation, and other exercise-related changes as possible contributors.

Researchers Still Need to Find the Best Exercise

Dr. Broatch emphasized that many questions remain. Researchers still need to determine how much exercise is most effective, which types of activity provide the greatest benefit, and whether those recommendations should change for people who are already experiencing cognitive decline or have been diagnosed with a brain disease.

Even with those questions unanswered, the findings provide another reason to make regular movement part of everyday life.

"If nothing else, this is yet another reminder that regular movement - especially the type that lifts your heart rate - is so important for every part of your health. The earlier we can develop these good habits, the better as we age," Dr. Broatch said.