Building This Strength Could Be Key to Brain Health
- Austin Perlmutter MD
- 8 hours ago
- 4 min read
This science definitely has legs!
By Austin Perlmutter, MD
For decades, we’ve been told to prioritize aerobic exercise. Activities like jogging rose in mainstream popularity in the 1960’s and 1970’s, touted as an antidote to the increasingly sedentary lifestyles of middle-aged adults. Water aerobics had a moment in the 1980s, and novel aerobics like Zumba have sparked massive interest worldwide. Yet as it relates to brain health, most people could be missing out on one of the most important exercises and strengths to help protect against cognitive decline and dementia.
A growing body of scientific literature has focused on the critical role of healthy skeletal muscle mass as a predictor of current and future brain health. Our bodies are about 40% skeletal muscle by weight, but starting around our 30’s, we start losing this tissue at an increasingly rapid clip. This loss of skeletal muscle and function (known as sarcopenia) is an independent risk factor for a host of diseases and dysfunction, including worsened brain function and dementia.
It’s absolutely the case that building and maintaining muscle strength across the body is a good bet. For example, a recent analysis of participants in the FINGER study tracked about 600 people (average age around 69) for 2 years. Those with better muscle strength and function at the start of the study as measured through tests like grip strength and chair stand had better global cognition, memory, and executive function at the end after correcting for variables like age and comorbidities. However, in some recent publications, there’s a signal that building leg muscle may be especially key to brain health.
In a 2018 paper in The Journal of Lifestyle Medicine, researchers looked specifically at the association between leg strength and cognition in 1508 older adults, between 60–85 years. They adjusted for age, how much people exercised and other variables, and found that people with more leg strength showed 34% lower odds for having lower cognitive function.
A seminal paper published in 2016 in Gerontology entitled “Kicking Back Cognitive Ageing: Leg Power Predicts Cognitive Ageing after Ten Years in Older Female Twins” looked specifically at leg strength and brain function over a 10-year period. What made the study most unique is that it tracked 324 female twins, enabling the researchers to better control for the impact of genetics.
They started by bringing the women into the clinic to gauge their leg strength using an exercise machine. They also captured data on cognition and brain anatomy using an MRI scan. After 10 years, they brought them back in to do the brain testing again. After accounting for variables like medical conditions, IQ, diet and even birthweight, they found “A striking protective relationship” between leg strength and their brain testing. Specifically, women with more leg strength at the start had better brainpower 10 years later, and more grey matter on their brain scans. They conclude that “Interventions targeted to improve leg power in the long term may help reach a universal goal of healthy cognitive ageing.”
These types of papers are great, but even better is interventional data. In March of 2025, researchers published exactly that. 70 older adults with varying degrees of risk for mild cognitive impairment (a common precursor to dementia) had cognitive testing and brain MRI and were randomly assigned to either a leg muscle strength program or a waiting list group. After 12 weeks, the 50 people who completed the trial were reanalyzed. In those who received the leg strength intervention there was better cognitive testing and less brain shrinkage in a region of the brain involved in memory.
A subsequent 2023 paper looked at the effect of 12 weeks of leg-focused strength training versus no leg training in 41 older adults. They performed advanced brain imaging to look at changes in brain chemicals during this period and found that that increases in leg strength correlated with elevations in key brain molecules “that correspond to exercise-induced “preservation” of brain health…” a technical way of describing the fact that leg training could beneficially alter brain chemistry.
How Leg Strength Could Boost and Protect the Brain
A number of pathways and physiological benefits link leg muscle with brain health. One of the more unexpected relates specifically to falls. Fall risk is a key modifiable risk factor for brain health and general survival. Research shows that lower leg power predicts higher fall risk in older adults. As falls are a leading cause of traumatic brain injury (TBI) in this population, and TBI may increase dementia risk up to 4-fold, this is a major consideration.
Leg strength is also directly linked to the brain by way of molecules called myokines-muscle-derived signals that may help promote beneficial immune, metabolic and brain cell rewiring effects. While resistance training in general is one of the best ways to boost levels of these brain-friendly molecules, the largest muscles in the body are in our legs and therefore, targeting leg exercises may be a particularly effective way to raise them.
How to Improve Leg Strength
Like anything that targets long-term brain health, consistency here is the key. Doing a couple heavy sets of leg press in the gym once a month might feel great, but a regular schedule of weekly leg training over months and years is far more likely to lead to longitudinal benefit.
How much time is needed? Although there is variability in the research, the studies mentioned above have focused on 12 weeks of intervention with exercise session about 2 times a week for 3 sets of 4 different leg exercises (e.g., leg press, leg curl) into show potential brain benefits. Importantly however, there’s plenty of value to doing any amount of additional leg exercise, especially if it sets the stage for a future routine.
Since most people tend not to prioritize leg exercises, it’s key to guard against injury and overuse especially for anyone ramping up or starting a routine. Working with a personal trainer is an excellent way to help lower risk for injury and to create a tailored routine to your personal needs (e.g., if you’ve had a knee replacement or have existing balance issues). While weighted movements like squats, deadlifts, and lunges are effective at activating multiple large leg muscle groups starting with lower intensity, body weight or even less resistance can all be options, depending on the individual.
This content is for informational and educational purposes only and does not constitute medical advice. Please consult with a qualified healthcare provider before making significant changes to your diet or lifestyle.
