Experts have long emphasized the value of staying active throughout life, but new research suggests that when you exercise may be just as important as how much you exercise—especially when it comes to protecting your brain. While early-life activity is beneficial, a recent study indicates that being physically active from your mid-40s onward may play a far greater role in lowering dementia risk.
The study, published in JAMA Network Open, analyzed thousands of adults and found striking results: individuals who maintained the highest levels of physical activity in midlife (ages 45–64) reduced their dementia risk by 41%, while those who stayed active in later adulthood (ages 65–88) saw a 45% reduction. These findings suggest that maintaining movement during these periods may create a powerful buffer against cognitive decline.
A neurologist involved in brain-health research noted that the study shifts the conversation from the general idea that “exercise is good” to the more precise concept that certain life stages may be essential windows for brain protection. With global dementia cases expected to rise dramatically in coming decades, understanding these windows has become increasingly urgent.
WHY MIDLIFE AND LATER YEARS MATTER MOST
The researchers wanted to determine whether physical activity has the same impact at all ages or whether the effects intensify during specific periods of adulthood. The study grouped participants by age: early adulthood (26–44), midlife, and late life. Interestingly, early-adulthood activity showed no significant link to dementia risk, while activity in both midlife and later years had strong associations with better brain outcomes.
One limitation, according to the study’s authors, is that their measurement method didn’t specify exact amounts of exercise. They used a combined score reflecting daily hours spent sleeping, sitting, or engaging in various intensities of movement. Still, the takeaway was clear: any increase in activity, especially moderate and vigorous movement, appears beneficial.
Other research offers clearer guidelines. A 2022 study showed that people who walked at least 3,800 steps a day lowered their dementia risk by 25%, with steadily rising benefits at higher step counts. Replacing car or bus rides with cycling has been linked to reduced risks of both general dementia and Alzheimer’s disease.
HOW MUCH EXERCISE IS ENOUGH?
Global health guidelines recommend 150 to 300 minutes of moderate exercise each week—or 75 to 150 minutes of vigorous activity. Examples include brisk walking, running, cycling, swimming, or structured cardio workouts. Strength training a few times per week also supports long-term brain health.
If you’re new to exercising, experts suggest starting slowly to avoid injuries that could limit your ability to stay active. Small daily habits—such as a 20-minute walk before work or brief movement breaks during the day—can help build consistency.
WHAT THE STUDY FOUND ABOUT GENETICS AND ACTIVITY
The findings came from participants in a long-running heart-health study. Even older adults with the APOE ε4 gene — one of the strongest genetic risk factors for Alzheimer’s — benefited significantly from staying active. In fact, high physical activity was associated with a 66% lower dementia risk among this group.
The authors noted some limitations: people who report higher activity levels may also have healthier lifestyles overall, and the study lacked detailed activity records from participants’ earlier years. Future research using wearable trackers may provide more precise insight.
WHY THESE LIFE STAGES ARE CRUCIAL
Experts believe midlife and late adulthood are critical because this is when common vascular problems—such as high blood pressure, diabetes, elevated cholesterol, and thyroid issues—tend to develop. Since vascular health is closely tied to cognitive decline, exercising during these years may offer powerful protection. Activity also supports brain structure, reduces inflammation, and may slow the accumulation of harmful proteins linked to Alzheimer’s.
If you’re thinking about changing your exercise routine, doctors recommend balancing physical activity with overall lifestyle habits and discussing any risk factors with a healthcare professional.
