Regular physical activity may help the aging brain flush out harmful waste proteins that accumulate over time, according to a new review led by researchers at Victoria University (VU) in Australia.
The research
Dr. James Broatch and colleagues analyzed existing studies of the glymphatic system — a network that clears metabolic waste from the brain, and which is especially active during deep sleep. Their paper, "Exercise as a regulator of glymphatic function," was published in Trends in Neurosciences in 2026.
The team reviewed data from both animal and human studies. They found that exercise appears to support glymphatic function through several connected pathways:
- Lowering blood pressure and reducing vascular stiffness
- Improving neuron activation in the brain
- Reducing brain inflammation
- Lowering resting norepinephrine levels
- Improving sleep quality, including deeper slow-wave sleep linked to waste clearance
The findings are especially relevant because more than 10 million people worldwide are diagnosed with dementia each year, and there is currently no cure. Broatch notes that the glymphatic system becomes more important with age, but sleep quality often declines at the same time — creating a potential double bind.
"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," Broatch said. "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."
Why it matters
This review adds a new mechanism to the well-established link between exercise and brain health. Rather than simply improving mood or blood flow, movement may help the brain's own waste-disposal system work more efficiently — particularly during sleep. For anyone concerned about cognitive decline, it suggests that regular aerobic activity could be one of the most accessible tools for protecting long-term brain function.
Broatch cautions that many questions remain: how much exercise is optimal, which types work best, and whether recommendations should differ for people already experiencing cognitive decline. His team is currently conducting further research.
What you can do
You don't need a laboratory to act on this. Aim for regular movement that raises your heart rate — brisk walking, cycling, swimming, or dancing. Pair it with consistent sleep habits: a cool, dark room, a steady bedtime, and limited screens before bed. Both exercise and sleep appear to support the same cleanup system.
"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," Broatch said.
Source: ScienceDaily Mind & Brain
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