Life Videos

Why Leg Strength Is the Best Predictor of Brain Health for Women Over 40 | Dr. Tommy Wood

Dr. Tommy Wood explains that leg strength, especially relative leg power, is a surprisingly strong predictor of cognitive processing speed for women past the age of 40. The discussion draws on NHANES data linking higher leg power—adjusted for body size—to better brain function, and highlights the biological mechanisms behind the connection. The core insight is that powerful legs signal both an active lifestyle and the release of exercise‑derived hormones, or exerkines, such as IGF‑1, which support white‑matter integrity. White‑matter health is a leading marker of age‑related cognitive decline, and randomized trials show resistance training can reverse white‑matter deterioration and boost cognition. Importantly, the benefit plateaus once individuals reach roughly the top 25 % of the population’s strength distribution. Wood illustrates the concept with personal anecdotes—reaching 700 watts on a bike sprint and comparing leg‑extension loads to body weight—while emphasizing that you don’t need to dominate every gym session. A simple regimen of one to two 30‑45‑minute workouts per week, covering five to six full‑body exercises, is sufficient to secure the protective effect. For women over 40, the implication is clear: modest, consistent strength training can serve as a low‑cost, high‑impact strategy to preserve brain health and lower dementia risk, making it a practical addition to any wellness routine.