Muscle Health = Brain Health: And Here is Why!

Age related neurological diseases, such as dementia and Alzheimer’s, are among the fastest growing morbidities worldwide. Programs designed to slow or combat these diseases are critical to the health of the American population. In 2017, about 49 million people were over the age of 65 and that number is expected to double in America by 2060. (Fang) With that increase will come a greater demand on the health system since the number of people with neurological diseases will also increase. (Fang) What can be done to slow the increase in neurological diseases as people age!

Dementia, including Alzheimer Disease, is a frightening disease. Because once you have a Dementia, your mind does not allow you to understand what you have and why you have it – your cognitive ability is either terribly weakened or gone. When we have cognitive health and have a disease like cancer, Type 2 diabetes, hypertension or cardiovascular disease, we can comprehend what we have and what needs to be done to help resolve the medical issue. Dementia is different. As the disease progresses, we no longer have the cognitive ability to comprehend what is happening.

Today, much research is being done to better understand the various dementia diseases including Alzheimer’s. Many new drugs are coming on the market to slow these diseases. Recent research even shows that muscle during physical activity releases a myokine that is protective against dementia.

But it is important to understand how the normal aging process affects brain health. What is critical to brain health is blood flow. As we age, vascularization with the brain begins to diminish. As this happens, it is more difficult to deliver the appropriate nutrients (mainly oxygen and glucose) to the brain. With age, critical brain structures like grey matter, white matter, hypothalamus and other structures, which are critical to neurocognitive health, shrink creating a negative impact on cognitive function. (Tarumi)

The brain is a high-blood flow, low resistance organ. One reason is the brain does not have the ability to store nutrients (such as glucose) needed for healthy neuronal activity and cognitive function. The brain accounts for about 20% of whole-body metabolic rate even though the brain only accounts for about 2% the total body mass. (Tarumi)

Keeping the blood vessels to the brain healthy and open is critical to maintaining a healthy brain. Physical activity (aerobic and resistance training) increases cerebral blood flow delivering more oxygen and nutrients to the brain (enhances vascularization). Further, physical exercise improves vascular function, such as reduced arterial stiffness and promotes neuroplasticity, in the brain. (Tarumi)

Select organs in the body communicate with one another via proteins/hormones called cytokines and this is called “Organ Cross-Talk”. (Valenzuela, Mikkelsen)

Not all organs cross-talk. Muscle cross-talks with the brain, the gut, adipose tissue, liver, bone and the pancreas. (Bettariga) Muscle and brain form a Muscle-Brain axis to cross-talk. (Bettariga, Burtscher) This is critical because one of cytokines released from muscle (myokines) during physical exercise is called irisin. Irisin has been shown to enhance cognitive function and has a positive impact on the presence of the brain-derived neurotropic factor (BDNF), also critical to healthy cognitive function. (Bathina, Islam)

According to Drs. Tsai and Pan, “memory function may be strengthened by the irisin-BDNF axis since irisin may increase BDNF synthesis and further augment neuroplasticity which in turn counteracts the negative cognitive consequences of age-related changes in the aging brain”.

According to Drs. J. and M. Burtscher, “regular appropriate exercise benefits many organs, including the brain. Exercise-stimulated muscle-brain cross-talk likely constitutes an important factor for brain health, attenuation of cognitive decline, and prevention of dementia”.

The effects of physical activity on irisin and BDNF are short term. Meaning once these compounds are released into the blood they could last up to 24 hours but most likely less than 1-hour. This is why to reap the benefits of irisin and BDNF, performing daily physical activity is necessary. Further, the research shows individuals who are lifetime exercisers realize the greatest impact of physical
activity on long-term brain health. Meaning the younger one starts to be physically active, the greatest the benefit. (Ferreira) But there are still benefits even for those who start being physically active at an older age. But without daily physical activity, aging decreases the availability of irisin and BDNF. (Tsai)

The implication of slowing dementia and related diseases through physical activity programs are critical to the health and well-being of all Americans. Industry should promote awareness programs to inform employees of the benefits of daily physical activity on brain health.

The research on muscle health and brain health is very new and exciting. For example, myokines released from muscle was discovered in 2012. (Sadier) There are over 600 myokines discovered so far but only detailed information on a couple dozen of the myokines has been researched. (Bettariga) Irisin is one of those myokines. As we learn more about these myokines as related to the body’s health, they will provide more detail as to why it is necessary to be physically active.

The body provides us great internal resources to be healthy. The question is, are we willing to take advantage of these resources?

References:

Bettariga, F., et.al, Exercise training mode effects on myokine expression in healthy adults: A systematic review with meta-analysis. Journal of Sport and Health Science. 2024: 13; 764-779

Bathina, S. and Das, U. Brain derived neurotrophic factor and its clinical implications. Arch Med Sci. 2015: 11(6); 56342

Burtscher, J. and Burtscher, M. Training muscle to keep the aging brain fit. Journal of Sport and Health Science. 2024: 13; 761-763

Fang, M., et.al., Lifetime risk and projected burden of dementia. Nature Medicine. 2025: https://doi.org/10.1038/s41591-024-03340-9

Ferreira, L.G., et.al., Effect of exercise detraining in cognitive functions of older adults: A systemic review. Archives of Gerontology and Geriatrics. 2024: 125; 105485

Islam, M., et.al. Exercise hormone irisin is a critical regulator of cognitive function. Nat Metab. 2021: 3(8); s42255-021-00438-z

Mikkelsen, K., et.al. Exercise and mental health. Maturitas. 2017: 106; 48-56

Sadier, N., et.al. Irisin: An unveiled bridge between physical exercise and a healthy brain. Life Sciences. 2024: 339; 122393

Tarumi, T., et.al., Aerobic exercise training for the aging brain: Effective dosing and vascular mechanism. Exercise and Sports Science Review. 2025: 53(1); 31-40

Tsai, C. and Pan, C. Acute and protocol-dependent effects of aerobic exercise on neurobiochemical indices and neuropsychological performance of working memory. Mental Health and Physical Activity. 2023: 24; 10094

Tsai, C., et.al, Acute effects of high-intensity interval training and moderate-intensity continuous exercise on BDNF and irisin levels and neurocognitive performance in late middle-aged and older adults. Behavioural Brain Research. 2021: 413; 113472

Valenzuela, P., et.al. Exerkine response to acute exercise: Still much to discover. Journal of Sport and Health Science. 2024: 13; 759-760