Skeletal Muscle’s Impact on Healthspan
Highlighting the importance and role of skeletal muscle—beyond just looking good naked.
Since the golden age of bodybuilding back in the 70s, there hasn’t been a movement this impactful on the desire to build a muscular physique, until today. The most recent influx of interest in muscle building is happening as we speak.
We’re living in a new era of gym-goers—and we’re here for it.
Men and women alike are striving not only to maintain lean physiques but they’re approaching their training with the intent to add more muscle to their frame. Sure, this drive may stem from a place of vanity, wanting to look good and feel good in their skin. However, not many understand the lasting impact of this lifestyle choice on their bodies' longevity.
Building and maintaining skeletal muscle does much more for our health than helping keep our bodies upright and mobile. It regulates many metabolic functions that occur beneath the surface. It is also a primary determinant of not just our life span but our health span as well.
Let’s dig into it.
Skeletal Muscle is the largest endocrine organ in the human body.
There are two very important factors to consider when talking about the role of skeletal muscle and the endocrine system:
1. The more frequently these muscle tissues contract, the more often a certain type of protein gets released. This protein is called myokines.
2. The more muscle tissue you have, the higher your mitochondrial density will be within that tissue.
Myokines have the great ability to communicate with other organs—such as adipose tissue, the liver, bones, and the brain—thanks to their autocrine, paracrine, and endocrine functions.
Within skeletal muscle itself, myokines support local muscle metabolism by protecting the functionality of the tissue and enhancing its capacity to handle various exercise intensities and workloads. When it comes to systemic metabolism, that’s where we start to see its involvement with other organs beyond muscular tissue (1).
These myokines aid in autocrine, paracrine, and endocrine functions such as body weight regulation, insulin sensitivity, suppression of tumor growth, improvement of cognitive functions, immunity support, fuel oxidation, hypertrophy, angiogenesis, and inflammatory responses (2). The more this protein is secreted, the more metabolically equipped we become to fight off illness, disease, and chronic health conditions.
Now, circling back to the second most important factor from earlier about the mitochondria.
Skeletal muscle is the primary source of glucose disposal.
Muscular tissue eats away at glucose when tasked with movement of various intensities. This is where our mitochondria kicks in. Its job is to take this available glucose and generate it into ATP—the primary source of energy for all physiological processes such as growth, movement, and homeostasis. The more mitochondria we have, the more glucose can be utilized for energy instead of storing the excess in our skeletal muscle and our liver.
Even with a decent amount of skeletal muscle, over time, undisposed glucose builds up in the liver and creates insulin resistance in the body. This means your organs no longer are responsive to the insulin secreted which leads to a lack of glucose uptake from your blood. It’s well documented that a prolonged period of high levels of blood glucose paired with insulin resistance is often a strong indicator of prediabetes. Continuously disposing of glucose to prevent it from building up within the blood is a sure way to maintain homeostasis in the body (3).
Skeletal Muscle helps you live longer.
Heart disease is still the leading cause of death in the world followed closely by cancer, stroke, Alzheimer’s, and diabetes. At the root, they are all correlated t
o the quality of your skeletal muscle.
Considering the role of myokines at the endocrine level and mitochondria in glucose disposal, it goes without saying that if you prioritize building muscle from a hypertrophy and/or strength perspective, you will undoubtedly protect yourself against these health conditions down the road (4).
The takeaway here is not only to build a huge amount of skeletal muscle but also to maintain it and keep it active. Skeletal muscle is very dependent on movement. It wants to contract, it wants to adapt, it wants to move—that’s the entire premise of its structure. This improves the quality of our tissues beyond just the total amount of lean mass we carry on our frame.
Aside from the metabolic benefits of skeletal muscle, being physically stronger also prevents the risk of falls and injuries as you age. Your bones become stronger as well, which helps decrease the likeliness of developing osteoporosis. By also having the ability to perform more physical tasks in your day-to-day, it improves your overall quality of life. Cooking, cleaning, dressing yourself, going out for a walk—little tasks that seem so minute can become much more substantial once you no longer have the same capabilities as before (5).
Live a long life but live your life.
The bottom line when it comes to skeletal muscle for health and from a medicine perspective, the best time to start prioritizing your tissue health is now. There’s no need for you to become the next powerlifting champion of your neighbourhood or for you to lift copious amounts of weight to reap the health benefits of skeletal muscle.
At the surface level, yes, any form of exercise has tremendous benefits for health, longevity, and improving your quality of life. Do your yoga, go run your 10km, and sign up for those spin classes! However, make sure to structure the basis of your training around strength work. Nothing else challenges skeletal muscle like heavy weight does.
**Author’s note: Dr. Gabrielle Lyon is currently pioneering the message of this piece. She is doing amazing work to bring forth her knowledge and discoveries about the role of skeletal muscle in longevity. I have been inspired by her from the get-go and I hope to be able to play a part in helping her lead the charge towards a new era of health. Imagine… 50 years from now, retirement homes are a thing of the past and our grandchildren have goals to keep up with us! Now, that’s a future I can sign up for.
Huh JY. The role of exercise-induced myokines in regulating metabolism. Arch Pharm Res. 2018 Jan;41(1):14-29. doi: 10.1007/s12272-017-0994-y. Epub 2017 Nov 25. PMID: 29177585.
Hoffmann C, Weigert C. Skeletal Muscle as an Endocrine Organ: The Role of Myokines in Exercise Adaptations. Cold Spring Harb Perspect Med. 2017 Nov 1;7(11):a029793. doi: 10.1101/cshperspect.a029793. PMID: 28389517; PMCID: PMC5666622.
Lee H, Song W. Exercise and Mitochondrial Remodeling in Skeletal Muscle in Type 2 Diabetes. J Obes Metab Syndr. 2018 Sep 30;27(3):150-157. doi: 10.7570/jomes.2018.27.3.150. PMID: 31089557; PMCID: PMC6504199.
Hood DA, Memme JM, Oliveira AN, Triolo M. Maintenance of Skeletal Muscle Mitochondria in Health, Exercise, and Aging. Annu Rev Physiol. 2019 Feb 10;81:19-41. doi: 10.1146/annurev-physiol-020518-114310. Epub 2018 Sep 14. PMID: 30216742.
Reimers CD, Knapp G, Reimers AK. Does physical activity increase life expectancy? A review of the literature. J Aging Res. 2012;2012:243958. doi: 10.1155/2012/243958. Epub 2012 Jul 1. PMID: 22811911; PMCID: PMC3395188.