It’s no secret that regular exercise benefits the body and mind. What is less well-known, however, is the central role that the leg muscles play in cognitive performance as we age.
“Stronger leg muscles are linked to better cognitive function in aging mainly through their effects on blood flow, metabolic health, brain structure, and physical/social activity patterns,” explains Dr. Chris Renna, DO, founder of the California-based, longevity-focused functional medicine practice LifeSpan Medicine. “Stronger leg muscles act as pumps that drive cerebral circulation during routine walking, delivering more oxygen and nutrients to your neurons. Muscular activity improves insulin sensitivity, increasing cell energy and reducing inflammation.”
Recent studies confirm that the activity of large muscle groups—especially in the glutes and thighs—has a direct influence on cognitive performance and age-related changes in the brain. This means that as the largest muscle groups in the body, the thighs and glutes not only influence mobility and metabolism, but also cognitive functions and age-related changes in the brain.
The reason for this lies in the biochemical communication between muscles and the nervous system. This can be explained as follows: When the leg muscles are activated during exercise, they release so-called myokines—hormone-like messenger substances that reach the brain via the bloodstream. There, they support processes that are relevant for learning ability, memory performance, and neuronal adaptability. At the same time, they promote blood circulation and have an anti-inflammatory effect, which is considered an important protective factor against neurodegenerative processes (processes in the nervous system in which nerve cells are gradually damaged or die).
Strong leg muscles support aging brains
When you train your leg muscles, you also support your brain. Several studies indicate that a decline in muscle strength in the legs can be associated with accelerated cognitive aging. One Canadian study that examined the muscle mass and the mental performance of older adults across several years found that those with lower muscle mass showed a significantly faster decline in certain cognitive functions—especially processing speed and executive function. People with well-preserved leg muscles performed better in tests of attention, processing speed, and memory than those with less developed leg muscles.
How periods of inactivity affect cognitive performance
For most of us, everyday life is characterized by a lack of movement. But those long hours sitting at a desk, commuting by car or public transport, and spending leisure time in front of screens also diminishes opportunities for the legs to be challenged.
When our large leg muscles remain inactive for long periods of time, the messenger substances that support our brains are also less active, providing our brains with less of what it needs to work optimally.
On the other hand, exercise—especially via the leg muscles—can supplement mental activity in a meaningful way. “Leg power predicts more grey matter in old age and less brain atrophy. Leg exercises stimulate BDNF, or brain-derived neurotrophic factor, which sustains and repairs damaged neurons,” says Renna.
There’s another brain benefit that’s less direct, but also essential when it comes to aging: “Perhaps most importantly, strong legs help us retain active, outgoing, and social lifestyles, whereas weak legs cause us to stay seated, sedentary, and often isolated,” notes Renna.
Leg muscles and the metabolism
Another point that has received increasing attention in recent studies is the influence of leg muscles on the metabolism—and thus, indirectly on the brain. Large muscle groups such as the thighs and buttocks play a central role in regulating blood sugar and insulin sensitivity. Both are crucial for the energy supply to the brain, which is dependent on a constant supply. Studies show that metabolic disorders, which are often associated with a lack of exercise, are linked to an increased risk of cognitive decline. Active leg muscles can support these processes and thus create an important basis for long-term brain performance.
The best exercises for strong legs and brains
Does all this mean that you need to do a crazy amount of squats, lunges, and heavy leg presses to keep your brain young? Not necessarily. The decisive factor is not so much the intensity but the consistency. As studies show, walking, climbing stairs, or moderate strength training for the legs is enough to activate the relevant processes—as long as you do it regularly.
But how much time do you really need to spend doing focused exercise? Renna says that any amount and any kind—walking, cycling, jogging, calisthenics, Pilates, or strength training is better than nothing, “but 150 minutes of exercise each week has been shown to add up to seven years to a person’s life.”
Remember, the entire body also benefits from simple everyday movements—taking the stairs instead of the elevator, walking instead of driving, and even shopping in-person instead of ordering online—and the benefits of regular exercise for all aspects of health can’t be understated. “Regular exercise impacts aging in several key ways: it reduces inflammation, slowing the wear and tear of daily life,” says Renna. “It improves sleep which helps cells and organs detox and recover overnight. It also affects telomeres—and the longer your telomeres, the longer you’ll live.”
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