How do strong muscles protect your brain?

 

Between your muscles and your brain, a complex molecular language is being communicated.

We've often thought of muscle as a separate entity from intellect—perhaps even as an adversary, with one draining resources from the other. The truth is that our brains and muscles are constantly communicating with one another, exchanging electrochemical signals. Our long-term brain health is directly related to keeping our muscles moving.

Skeletal muscle is one of the largest organs in the human body and allows you to move around. It's also an endocrine tissue, which means it sends signaling molecules to other parts of your body to tell them what to do. The protein molecules that send messages from skeletal muscle to other tissues that include the brain.

When your muscles contract, create new cells, or perform other metabolic activities, myokines are released into the bloodstream. When they reach the brain, they also regulate physiological and metabolic responses. As a result, myokines can influence cognition, mood, and emotional behavior. Exercise increases what scientists call muscle-brain "cross talk," and myokine messengers help determine specific beneficial brain responses. These can include new neuron formation and increased synaptic plasticity, both of which improve learning and memory.

Strong muscles are necessary for healthy brain function in these ways.

A small amount of exercise activates molecular processes that tell the muscle to grow. Muscle fibers are damaged by strain and stress and then repair themselves by fusing together and growing in size and mass. Muscles become stronger by surviving each series of minor breakdowns, which allows for regeneration, rejuvenation, and regrowth. The signal sent by exercise becomes much weaker as we age. Though it is more difficult for older people to gain and maintain muscle mass, it is still possible, and maintaining muscle mass is critical to brain health.

In older adults, even moderate exercise can increase metabolism in brain regions important for learning and memory. And it has been discovered that the brain responds to exercise in startlingly physical ways. The hippocampus, a brain structure important for learning and memory, shrinks in late adulthood, increasing the risk of dementia. Even late in life, exercise training has been shown to increase the size of the hippocampus, protecting against age-related loss and improving spatial memory.

Furthermore, there is strong evidence that certain myokines have sex-specific neuroprotective properties. The myokine irisin, for example, is influenced by estrogen levels, and postmenopausal women are more susceptible to neurological diseases, implying that irisin may also play an important role in protecting neurons against age-related decline.

Increased physical activity and motor skills have been linked to improved cognitive function in people with pre-existing brain disease or damage, according to research. Sarcopenia, or age-related muscle atrophy, increases the risk of cognitive decline. Exercising improves memory, processing speed, and executive function, especially in older adults, according to mounting evidence. Loss of skeletal muscle mass and function makes the brain more vulnerable to dysfunction and disease. (Exercise improves these cognitive abilities in children as well.)

Your muscles and brain communicate using a complex molecular language. Exercise helps us retain our fluency in that language even as we age.