Neurologist Dr. Jasmeer Chhatwal leaves his Harvard office every day in the early afternoon and walks two miles—part scientific habit, part daily ritual. It’s not just a coffee run; it’s an act of prevention on his part, linked to his research into brain aging and the earliest phases of Alzheimer’s disease. In a study in Nature Medicine, Chhatwal and his colleagues observed hundreds of cognitively healthy adults aged 50 to 90 for up to 14 years. They discovered that people who averaged about 5,000 to 7,000 steps per day — roughly two to three miles — had substantially less accumulation of tau protein (a hallmark of Alzheimer’s) as well as slower cognitive decline.
Their findings bolster an essential message: It’s not necessary to run marathons or spend hours at the gym to preserve your brain. “We live in the age of mixed messages,” Chhatwal himself said.“People don’t need to run marathons. In terms of what you can do for yourself and your brain, this is a pretty easy one, comparatively speaking. What makes the research notable is that it ties walking and physical activity not only to general health but also to specific Alzheimer 's-related biomarkers, such as tau buildup. Walking at least 3,000 steps a day (a little less than 1½ miles) was associated with measurable benefits as people got older — even for those who were already showing signs of amyloid protein build-up in the brain, a precursor to tau and cognitive decline.
What is it about walking that makes a difference? Researchers point to multiple mechanisms. Exercise increases blood flow to the brain, reduces inflammation, enhances the production of neuroprotective proteins like brain-derived neurotrophic factor (BDNF), and may even help clear toxic protein buildup through the glymphatic system. In the Chhatwal study, those with higher amyloid who engaged in more walking showed a smaller increase in tau and a slower overall decline in cognition and daily function. The bottom line: even if you have known Alzheimer’s risk factors now, lifestyle habits may be able to shift the trajectory of your brain health.
For the layperson, something as simple as taking an afternoon walk — Chhatwal’s coffee walk being one potent example — can be helpful. It doesn’t require a gym membership, fancy equipment, or a clothes-off-your-back time commitment. Consistency matters. A straightforward response might be to strive for 5,000 steps (about 2 miles) daily, which may sound like a lot if you’re currently sedentary; if so, shoot for 3,000 and gradually increase. Not sitting for long periods of time is also essential; other research has shown that excessive sedentary behavior independently predicts brain shrinkage and cognitive decline — even in adults who exercise to meet physical-activity recommendations.
There are some nuances. The participants in the study were largely well educated and not necessarily representative of the U.S. population as a whole. Also, because the research is observational, it demonstrates association rather than definite causation. But even if a stroll is no guarantee against Alzheimer’s, the risk-reward ratio is a good one: minimal cost, minimal pain, potentially measurable upside.
So how do you translate this into action? To begin with, incorporate walking into daily life — walk to work, take walking meetings, and use stairs. Second, count your steps — even with a bare-bones app, you’ll chart your progress and shore up consistency. Third, accompany your walking with other habits that keep the brain healthy: control high blood pressure, engage in cognitive work, get restful sleep, and don’t smoke. The result is more potent effects than any one move alone.
Chhatwal’s daily workout is a reminder that even Alzheimer’s researchers take common-sense steps — they walk, literally — to stay one step ahead of brain aging. His two-mile daily walk isn’t going to rock anyone’s world, but it may be one of the best investments your brain ever makes. For those thinking on an even grander scale of health, the simplest tools are often the most powerful.
