Scientists are investigating whether regular movement helps the brain perform its nightly “clean-up” more effectively. Credit: Shutterstock

A new study strengthens the case for exercise as a critical way to protect the brain from age-related decline, including dementia and Alzheimer’s disease.

During sleep, the brain activates a cleanup network that helps remove accumulated waste. A review led by Victoria University (VU) researcher Dr. James Broatch examined whether exercise could strengthen this glymphatic system, which becomes increasingly important for maintaining brain health as people age.

Exercise is already closely associated with healthy aging, but exactly how it protects the brain remains uncertain. Understanding that mechanism is especially important because more than 10 million people worldwide are diagnosed with dementia each year, and no cure currently exists.

Published in Trends in Neurosciences, the peer-reviewed paper evaluated existing animal and human research on the glymphatic system. Although more evidence is needed (including research Dr Broatch is now conducting), the review found that exercise improves several biological processes involved in regulating brain waste clearance.

Exercise supports brain waste clearance

The reported effects include:

• Lower blood pressure and reduced vascular stiffness
• Improved activation of neurons in the brain
• Reduced inflammation in the brain
• Lower resting norepinephrine levels
• Better sleep, including improved deep sleep and increased slow wave activity associated with waste clearance

Dr. Broatch said the connection between exercise and brain protection could help researchers identify scientifically supported physical activity strategies for limiting 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.

The best exercise dose remains unclear

Researchers still need to establish which forms of exercise are most effective, how much activity is required, and whether recommendations should change for people already experiencing cognitive decline or living with a brain disease.

“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.

Reference: “Exercise as a regulator of glymphatic function” by James R. Broatch, Nicholas J. Saner, Melinda L. Jackson, Warda Syeda, David J. Bishop and Amy Brodtmann, 29 June 2026, Trends in Neurosciences.
DOI: 10.1016/j.tins.2026.06.002

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