A landmark 10-year study of over 300 pairs of female twins reveals that women with stronger legs enjoy significantly healthier brains as they age. Researchers followed twins aged 43–73 and found that, in virtually every pair, the sister with greater leg power at the beginning of the study showed sharper memory, faster thinking, and less brain aging a decade later—outperforming her genetically identical twin even when lifestyle factors were otherwise similar. Remarkably, leg strength turned out to be a stronger predictor of long-term cognitive health than any other variable measured, including diet, exercise volume, or education. The best part: you don’t need heavy weightlifting to reap the benefits. Simple daily habits—walking regularly, taking the stairs, gardening, dancing, or even brisk shopping trips—build and maintain leg strength while also boosting brain resilience. Staying socially active through clubs, volunteering, or meetups adds another powerful layer of protection. In short, keeping your legs strong and active may be one of the easiest, most effective ways to keep your mind sharp well into later life.