Walking 5,001 to 7,500 steps a day slows the buildup of tau, the brain protein linked to Alzheimer's-related decline, helping you stay sharper for years longer Older adults with elevated amyloid — a key early Alzheimer's marker — preserved memory and daily function far better when they consistently reached a moderate step range Even small increases in movement, such as moving from under 3,000 steps to 3,500 to 5,000 per day, deliver meaningful cognitive benefits without requiring intense exercise High-intensity training pushed healthy adults into metabolic dysfunction, reducing mitochondrial energy production by about 40% and disrupting blood sugar stability Finding your personal exercise "sweet spot" — enough movement to avoid inactivity without pushing into extreme training — protects both long-term brain health and daily metabolic balance