Metabolism, Immunity, Blood flow and More...
By Austin Perlmutter, MD
When we talk about the most evidence-based recommendations on protecting the brain from conditions like dementia, stroke and depression, exercise is always at the top of the list. People who move more live longer, feel better and have better functioning brains. But why? One of the most important reasons is the muscle-brain connection. In this article, we’re breaking down this incredible bidirectional pathway and the steps you can take today to enhance your brain health by optimizing muscle function.
The Basics: Muscles and the Brain:
Muscles in the human body can be classified into three main types: skeletal muscle, cardiac muscle, and smooth muscle. Each type has unique characteristics, locations, and functions, contributing differently to the total muscle mass in a typical person. When it comes the muscle-brain connection, the best studied type is skeletal muscle, which makes up about 40% of our muscle mass and our largest muscles (like our quadriceps, gluteus maximus and latissimus dorsi (back muscles).
Our brains and muscles are connected through a number of molecular pathways. Among the best studied of these relate to our vascular system, our immune system, our metabolism and neurotrophins (molecules like brain-derived neurotrophic factor, or BDNF).
Muscle health improves brain immunity
The immune system is closely linked to both muscle and brain health. Exercise has been shown to modulate immune function, which in turn influences neuroinflammation – a critical factor in neurodegenerative diseases such as Alzheimer's, Depression and Parkinson's. One of the key mediators in this process is a group of proteins called myokines.
Myokines are tiny molecules (technically cytokines or peptides) produced and released by muscle fibers in response to muscular contractions during exercise. One such myokine, interleukin-6 (IL-6), has dual roles; it can act as a pro-inflammatory or anti-inflammatory agent depending on its context. During exercise, IL-6 released from muscles exerts anti-inflammatory effects, which can reduce chronic systemic inflammation, a known risk factor for cognitive decline and neurodegenerative diseases . The bottom line is that activating, growing and caring for your muscles maintains a balanced immune response, reduces the risk of chronic inflammation, and therefore helps protect brain health.
2. Muscle health boosts brain metabolic health
Exercise also exerts significant effects on metabolic processes that are essential for brain function. The brain is a highly energy-demanding organ, and its function relies on a steady supply of glucose and oxygen. Physical activity enhances insulin sensitivity and glucose metabolism, ensuring that the brain receives adequate and stable energy. Large skeletal muscle use is of particular importance here. That’s because our big skeletal muscles (like our leg muscles) suck up excess glucose from our blood when we exercise them, helping to stabilize blood sugar levels.
Additionally, exercise-induced myokines like irisin, which is released during physical activity and especially during resistance training. Irisin is now being studied for its positive effect on metabolism, specifically by increasing the conversion of white fat to beige fat (this helps overall health and metabolic health).
3. Muscle health enhances neuroplasticity
Neuroplasticity, the brain's ability to reorganize itself by forming new neural connections, is fundamental to learning, memory, and overall cognitive health. Exercise has been shown to enhance neuroplasticity through various mechanisms.
One primary way exercise promotes neuroplasticity is by increasing cerebral blood flow, which delivers more oxygen and nutrients to brain cells. This improved blood flow stimulates the release of growth factors, including BDNF and insulin-like growth factor 1 (IGF-1), which support the growth and survival of neurons. BDNF levels have been clearly shown to increase in people who do both aerobic and resistance training.
How to Optimize Your Muscle-Brain Connection
When it comes to improving muscle health to improve brain health, you want to think about sustainable strategies that help build and maintain muscle over the lifespan. This isn’t about competing in a bodybuilding tournament; it’s about having better brain health! There is no shortage of books, podcasts, articles and more on the topic of muscle health, but here are several key basic strategies to consider.
Prioritize weight/resistance training
Training with weights and resistance bands can help increases muscle mass, strength, and endurance, while enhancing metabolic and immune health and producing high levels of brain-boosting myokines. Resistance bands can be an excellent support tool here, and if you haven’t done weight training before, consider working with a trainer to get you started safely.
2. Do aerobic exercise: Activities like running, swimming, cycling, and brisk walking activate multiple muscle groups while increases heart rate and blood flow to the brain. These exercises are particularly effective in boosting BDNF levels and enhancing cognitive functions such as memory and executive function.
3. Get enough protein: Right now, there’s a lot of confusion around how much protein intake is best, and many people advocating for specific and highly variable daily protein intake. However, most agree that at the least, we need 0.8 grams of protein per kilogram of body weight for the average adult (0.36 grams per pound). If you’re active, over age 65 and or trying to build muscle, increasing this may make a lot of sense, and getting closer to 1.2-2 grams per kg may make sense. Talking with your nutrition expert/healthcare provider about your personal goals.
4. Consider supplemental creatine monohydrate: Creatine is a well-studied supplement that has uniquely been linked to better muscle health and brain health. research suggests that people may benefit from taking around 3.5-5 grams a day, but make sure to speak with your health provider about your specific use.
Excellent article, very interesting!