Today’s subject? Muscle mass and sharper thinking.
I regularly lift weights.
A growing body of evidence shows that exercises positively impact health, age-related decline, and longevity.
Of course, we should pair out physical activity with other health-promoting practices:
Longevity: Is exercise the key to a longer, healthier life?
A new study found that while exercise is important to a long life, following other healthy lifestyle habits may…www.medicalnewstoday.com.
Exercise and aging: Can you walk away from Father Time – Harvard Health
The clock ticks for all men, and with each tick comes change. For men who manage to avoid major medical problems, the…www.health.harvard.edu
My Objectives – Muscle Mass and Sharper Thinking
I have written about how exercise benefits us, from improving cardiovascular health and reducing the risk of chronic diseases to extending our lifespans.
Today, I want to focus on how physical activity might enhance your cognitive function.
More specifically, I will focus on how myokines — peptides or proteins secreted or released from skeletal muscle cells — can influence other tissues and organs of the body.
In simpler terms, myokines are messengers that muscles send to tell other parts of the body to stay healthy and strong.
Exercise and The Brain – Muscle Mass and Sharper Thinking
Do you think of skeletal muscle as a tool required for movement?
If you answered yes, I have no quibble.
You may be surprised to learn that skeletal muscle also functions as an endocrine organ.
Think of the muscle as releasing various peptides and proteins — collectively known as myokines — which act as signaling molecules to other body parts.
Myokines: Muscles Messengers
The link between muscle mass and cognitive function lies in the intricate interplay between muscle and brain, mediated by myokines.
A myokine is a peptide or protein secreted or released from skeletal muscle cells.
These signaling molecules, released by contracting muscles, act as messengers that travel through the bloodstream and directly influence the brain.
Myokines are skeletal muscle messengers communicating with tissues and organs throughout our bodies.
Let me get a bit more technical: Myokines act through several mechanisms:
- autocrine (acting on the muscle itself)
- paracrine (acting on nearby cells)
- endocrine (acting on distant organs) mechanisms.
Myokines Are Big Influencers
Myokines influence a diverse range of physiological processes, including:
- Metabolism: Regulating glucose uptake, lipid metabolism, and energy expenditure.
- Inflammation: Modulating immune responses and reducing inflammation.
- Brain Function: Promoting neurogenesis, enhancing cognitive function, and protecting against neurodegenerative diseases.
- Cardiovascular Health: Improving endothelial function, reducing blood pressure, and protecting against heart disease.
- Bone Health: Stimulating bone formation and preventing bone loss.
Health and Disease Implications
The endocrine function of skeletal muscle has profound implications for health and disease.
- Exercise as Medicine: Regular physical activity stimulates the release of beneficial myokines, promoting overall health and reducing the risk of chronic diseases.
- Muscle Loss and Disease: Conversely, muscle loss (sarcopenia) and inactivity are associated with decreased myokine production, contributing to the development of various conditions, including metabolic syndrome, cardiovascular disease, and cognitive decline.
Myokines and Cognitive Functioning: Details
Here are some key elements of the myokine/brain story:
- Myokines as neuroprotective agents: Certain myokines, like cathepsin B, cross the blood-brain barrier and stimulate neurogenesis, the growth of new neurons. Others have anti-inflammatory effects, protecting the brain from damage.
- Positive feedback loop: Myokines often trigger the release of more myokines, amplifying their beneficial effects. This release creates a positive cycle where muscle activity promotes brain health, which in turn can enhance muscle function.
- Negative spiral of inactivity: Conversely, physical inactivity reduces myokine production. Diminished myokines have negative effects, including impaired mitochondrial function, inflammation, and cognitive decline.
The Weightlifting: Brain Function Link
We have low-level evidence that low muscle mass makes you more likely to have cognitive impairment.
Unfortunately, most available evidence is from epidemiologic studies, which typically cannot demonstrate causality.
The existing research linking low muscle mass to cognitive decline aligns well with the criteria for establishing causality.
Low Muscle Mass Causes Brain Issues
Here are some of the reasons that I believe having low muscle mass can result in cognitive impairment:
- Strong Association: Numerous studies have consistently demonstrated a significant association between low muscle mass and cognitive decline. Individuals with lower muscle mass are more likely to experience cognitive impairment than those with higher muscle mass.
- Dose-Dependent Relationship: The association often appears dose-dependent, meaning that the lower the muscle mass, the greater the risk of cognitive decline. Muscle mass may play a causal role.
- Consistency Across Studies: The link between low muscle mass and cognitive decline has been observed across various populations and study designs, strengthening the evidence for a causal relationship.
- Biological Plausibility: As discussed earlier, this link has a strong biological rationale. Myokines, the signaling molecules released by muscles, have been shown to impact brain health directly. Reduced muscle mass can decrease myokine production, potentially contributing to cognitive decline.
- Temporal Relationship: While more longitudinal studies are needed, some research suggests that low muscle mass precedes cognitive decline, further supporting that it’s a contributing agent rather than just a consequence of aging.
- Strength of Association: The magnitude of the association between low muscle mass and cognitive decline is often substantial, suggesting a clinically relevant impact.
Of course, we need further research to confirm causality.
However, the existing data strongly suggest that low muscle mass is not merely a marker of cognitive decline but a potential causal factor.
Implications for You – Muscle Mass and Sharper Thinking
- More than just a bonus: Exercise is essential for maintaining the myokine-mediated communication between muscles and the brain.
- Inactivity as a detriment: Physical inactivity actively impairs this communication, leading to a decline in overall health and cognitive function.
Into the Future – Muscle Mass and Sharper Thinking
Research into the endocrine function of skeletal muscle is rapidly expanding.
Scientists continually identify new myokines and unravel their complex roles in health and disease.
This knowledge holds great promise for developing novel therapeutic strategies to prevent and treat various conditions.
Understanding the endocrine function of skeletal muscle opens up a new dimension in our appreciation of its importance for overall health.
It’s a testament to our body’s connectedness and highlights the power of exercise as a potent medicine.
And yes, I went to the gym this morning for resistance training.
Has this essay changed your perspective about skeletal muscle as only a tissue responsible for movement and force generation?
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drmichaelhunter.medium.com
Thank you for reading “Muscle Mass and Sharper Thinking.”
