Your Legs Are Keeping Your Brain Alive — Are You Using Them? A 10-year twin study followed identical female twins and found that the sister with stronger legs had up to 47% lower risk of dementia — same DNA, different brain, because one of them trained four days a week on her leg muscles. Every increase in muscle strength at baseline was associated with roughly a 43% decrease in the risk of Alzheimer's disease. The research is clear: strong legs send protective signals directly to the brain. Pick up the weights — your future mind is counting on it.