Understanding why skeletal muscle functions as an endocrine organ, how exercise activates communication between organs, and why maintaining muscular health is essential for metabolism, immunity, brain function, and healthy aging.
When most people think about skeletal muscle, they think about movement.
Muscles allow us to walk, run, lift objects, maintain posture, and perform everyday activities.
They contribute to strength, endurance, athletic performance, and physical independence.
For decades, these mechanical functions dominated our understanding of muscular health.
However, contemporary exercise physiology has revealed something extraordinary:
Skeletal muscle is not simply an organ of movement. It is also an active endocrine and signaling organ that communicates with tissues throughout the body.
Every time we exercise, contracting skeletal muscle initiates a coordinated series of biochemical responses.
Some of these responses occur locally within the muscle.
Others influence distant organs, including the liver, adipose tissue, pancreas, bones, and potentially the brain.
This communication involves a diverse collection of molecules known as myokines.
Myokines are proteins and peptides produced and released by skeletal muscle cells that can influence biological processes locally or elsewhere in the body.
Their discovery has fundamentally changed how researchers understand the relationship between movement and health.
In 2019, Grit Legård and Bente Pedersen published a chapter titled Muscle as an Endocrine Organ in the textbook Muscle and Exercise Physiology.
Their work synthesized decades of research demonstrating that contracting skeletal muscle releases signaling molecules involved in energy regulation, inflammatory responses, tissue adaptation, and communication between organs.
More recent publications in Nature Reviews Endocrinology, Nature Metabolism, and Nature Communications have expanded this perspective.
Researchers now recognize that exercise produces a system-wide molecular response involving not only muscle-derived factors but also signals from the liver, heart, adipose tissue, bone, and other organs.
These discoveries help explain why physical activity influences far more than muscular strength or cardiovascular fitness.
They also reinforce an important principle:
Movement is not merely something the body performs. It is a physiological stimulus that helps regulate how the body functions.
1. Skeletal Muscle: A Major Organ of Human Health
Skeletal muscle is one of the largest tissue compartments in the human body.
Its total mass varies according to age, sex, body size, physical activity, and health status.
Traditionally, muscle has been characterized by its ability to produce force through coordinated contraction.
However, muscle also plays a major role in metabolism.
It contributes substantially to glucose disposal following meals and serves as an important reservoir of amino acids.
Muscular activity influences energy expenditure, physical conditioning, and the body's response to metabolic demands.
During exercise, skeletal muscle increases its requirements for ATP, the primary energy currency supporting cellular activity.
These demands stimulate changes in glucose uptake, fat oxidation, blood flow, and intracellular signaling.
However, the effects of muscle contraction do not remain confined to the muscle itself.
Working muscles can release signaling molecules that influence other tissues.
This is the foundation of skeletal muscle's endocrine function.
2. What Are Myokines?
Myokines are cytokines and other peptides produced, expressed, and released by skeletal muscle fibers.
They can exert three general types of biological effects.
Autocrine signaling occurs when a molecule acts on the cell that produced it.
Paracrine signaling occurs when it influences nearby cells or tissues.
Endocrine signaling occurs when a molecule enters the circulation and affects distant tissues.
The 2019 Legård and Pedersen chapter describes skeletal muscle as a secretory organ capable of producing hundreds of different signaling factors.
Some participate in muscular growth and regeneration.
Others influence glucose metabolism, fat oxidation, inflammatory responses, or blood vessel function.
However, not every molecule detected in muscle is necessarily a biologically important circulating myokine.
Researchers must demonstrate that a molecule is produced by muscle, released under relevant conditions, and capable of producing meaningful effects.
This distinction has become particularly important as modern proteomic technologies identify increasingly large numbers of exercise-responsive proteins.
The presence of a protein in blood after exercise does not automatically establish that it originated from skeletal muscle.
3. How Scientists Discovered Muscle's Endocrine Function
The idea that working muscle releases substances capable of influencing other organs developed over many decades.
Researchers initially proposed the existence of an unidentified exercise factor.
The hypothesis emerged because contracting muscle appeared capable of influencing metabolism and physiology in ways not fully explained by conventional neural and hormonal pathways.
A major breakthrough occurred around 2000.
Researchers demonstrated that contracting human skeletal muscle releases significant quantities of interleukin-6, commonly abbreviated IL-6, into the circulation during prolonged exercise.
This discovery challenged the conventional understanding of IL-6.
Previously, IL-6 was studied primarily as an inflammatory cytokine.
However, its production by healthy contracting muscle suggested additional physiological roles.
Subsequent investigations demonstrated that muscle-derived IL-6 contributes to metabolic signaling during exercise.
These discoveries helped establish the concept of the myokine.
Since then, researchers have identified numerous additional molecules associated with muscular activity and tissue communication.
4. IL-6: Why an Inflammatory Molecule Can Also Support Adaptation
Interleukin-6 provides one of the clearest examples of why biological molecules cannot be understood without considering context.
IL-6 participates in inflammatory and immune processes.
Elevated IL-6 concentrations can occur during infections, chronic inflammatory disorders, obesity-associated inflammation, and other medical conditions.
However, IL-6 also increases during muscular exercise.
The biological circumstances surrounding these increases are different.
During exercise, skeletal muscle releases IL-6 in response to contraction-related metabolic demands.
The magnitude of the response depends partly on exercise duration, intensity, the amount of active muscle, and energy availability.
The 2019 Legård and Pedersen chapter describes how exercise-related IL-6 can influence glucose production, muscular glucose uptake, and lipid metabolism.
It can also contribute to downstream changes in immune signaling.
Importantly, exercise-induced increases in IL-6 can occur without muscle damage.
The Difference Between Exercise and Infection
During many infectious or inflammatory responses, increases in IL-6 occur alongside other inflammatory mediators, including tumor necrosis factor-alpha and interleukin-1 beta.
During exercise, IL-6 may rise without an equivalent preceding increase in these inflammatory cytokines.
Exercise can also stimulate the appearance of anti-inflammatory mediators, including IL-1 receptor antagonist and IL-10.
The accompanying endocrine and immune context therefore matters.
A 2022 Nature Metabolism perspective, Interleukin 6 as an Energy Allocator in Muscle Tissue, proposes that exercise-induced IL-6 helps coordinate the distribution of energy during physical activity.
Its authors argue that IL-6 participates in the temporary mobilization and allocation of metabolic resources.
This perspective challenges simplistic descriptions of IL-6 as either universally harmful or universally beneficial.
The function of a biological signal depends on when it is produced, where it acts, how long it remains active, and the physiological circumstances surrounding it.
5. How Exercise Helps Regulate Blood Glucose
Skeletal muscle is essential to glucose metabolism.
Following a meal, insulin helps coordinate glucose uptake and storage in various tissues.
Skeletal muscle represents a major site of insulin-stimulated glucose disposal.
However, muscle contraction can also stimulate glucose uptake through pathways that are not entirely dependent on insulin signaling.
During exercise, contraction-related processes promote the movement of glucose transporters toward the muscle-cell membrane.
This helps working muscles obtain the energy needed for continued activity.
Exercise also stimulates molecular pathways involved in energy sensing, including AMP-activated protein kinase, or AMPK.
Muscle-derived signaling molecules such as IL-6 may contribute to these coordinated metabolic responses.
Over time, repeated exercise training can improve insulin sensitivity and muscular oxidative capacity.
These adaptations are particularly relevant to individuals with insulin resistance or elevated cardiometabolic risk.
However, the benefits of exercise on glucose regulation arise through multiple mechanisms.
They should not be attributed exclusively to one myokine.
6. Exercise Is a Form of Communication Between Muscle and Liver
The liver helps maintain glucose availability during exercise.
As muscular energy demands increase, hepatic glucose production contributes to maintaining circulating glucose concentrations.
This process involves hormonal regulation and metabolic communication among tissues.
Research described in the 2019 chapter demonstrated that IL-6 can contribute to increased hepatic glucose production during exercise.
The investigators interpreted these findings as evidence of communication between working muscle and liver.
This is an important concept.
The liver does not simply respond independently to changing glucose concentrations.
It operates within a coordinated physiological system.
Working muscle generates energy demands and produces signals.
The liver responds through changes in substrate handling and glucose availability.
Other organs, including the pancreas and adipose tissue, also participate.
The result is a dynamic network that helps maintain energy supply during activity.
7. Muscle and Adipose Tissue: Two Communicating Organs
Adipose tissue is another important endocrine organ.
It produces numerous signaling molecules, commonly described as adipokines.
These include leptin, adiponectin, and other factors involved in metabolic and immune regulation.
The 2019 Legård and Pedersen chapter introduces a conceptual relationship between myokines and adipokines.
Muscular activity and adipose tissue both influence systemic signaling, but their effects can differ according to physiological circumstances.
For example, certain inflammatory signals are associated with excess visceral adiposity and metabolic dysfunction.
Regular exercise can improve metabolic health and may reduce visceral adiposity over time.
Muscle-derived factors can also influence lipid mobilization and energy metabolism.
However, it would be inaccurate to describe muscle as universally anti-inflammatory and adipose tissue as universally inflammatory.
Adipose tissue performs numerous essential physiological functions.
Its signaling profile varies according to location, metabolic health, and other factors.
Likewise, myokines can participate in both adaptive and pathological responses.
The important relationship involves the balance and interaction among tissues—not a simple competition between good and bad hormones.
8. Myostatin: A Regulator of Muscle Growth
Another important molecule discussed in the uploaded chapter is myostatin.
Myostatin is a member of the transforming growth factor-beta superfamily.
It plays an important role in limiting skeletal muscle growth.
Experimental studies demonstrate that disruption of myostatin signaling can produce substantial increases in muscular mass.
This has encouraged researchers to investigate myostatin inhibition for conditions involving severe muscle wasting.
However, reducing myostatin is not automatically equivalent to improving physical performance or health.
Muscle function depends on more than total size.
Strength, neuromuscular coordination, mitochondrial capacity, connective tissue properties, and movement proficiency also matter.
Furthermore, experimental changes in muscle mass do not always translate into proportionate improvements in functional performance.
Regular exercise can influence pathways associated with muscle growth and maintenance.
But the adaptations depend on training type, nutrition, recovery, age, and other factors.
9. Follistatin, Muscle Regeneration, and Interorgan Signaling
Follistatin is a regulatory protein that can interact with signaling pathways involved in muscle growth.
It can inhibit the activity of myostatin and related molecules.
The 2019 chapter discusses evidence that circulating follistatin increases following certain forms of exercise.
Experimental findings also suggest that the liver may contribute significantly to exercise-related follistatin production.
This creates another example of interorgan communication.
Muscle contraction can stimulate signals that influence the liver, while liver-derived factors may participate in pathways relevant to muscular adaptation.
However, these relationships are complex.
Follistatin is not simply a muscle-building hormone that should be maximized.
Its physiological effects depend on the signaling pathways and tissues involved.
Moreover, experimental manipulation of myostatin–follistatin pathways is not equivalent to ordinary exercise training.
For most individuals, progressive resistance exercise and appropriate nutritional support remain better-established approaches to improving muscular strength and function.
10. Irisin: An Emerging Link Between Muscle, Metabolism, and the Brain
Irisin is another molecule that has attracted considerable attention.
It is generated through the processing of the protein FNDC5.
Experimental studies have investigated whether exercise-related FNDC5/irisin signaling influences adipose tissue metabolism and neurological function.
Some animal studies suggest that irisin participates in metabolic adaptations and may influence processes involving neuronal health.
However, the scientific literature includes important uncertainties.
Researchers have debated aspects of irisin measurement, regulation, and the translation of experimental findings into humans.
A 2025 npj Parkinson's Disease review, New Perspectives on Molecular Mechanisms Underlying Exercise-Induced Benefits in Parkinson's Disease, discusses irisin among several candidate molecular pathways potentially contributing to neurological adaptations.
These mechanisms are scientifically interesting but remain incompletely established in humans.
The evidence does not justify using blood irisin measurements to determine whether someone is exercising adequately.
Nor does it establish that supplementation or manipulation of irisin signaling can reliably prevent neurodegenerative disease.
Irisin represents a promising research target rather than a validated clinical shortcut to the benefits of exercise.
11. Muscle–Brain Communication: How Movement May Influence Neurological Health
Exercise is associated with numerous neurological and psychological benefits.
These may include improvements in cognition, mood, sleep, and aspects of brain health.
Researchers are investigating whether circulating factors released during exercise contribute to some of these effects.
A 2019 Nature Reviews Endocrinology review, Physical Activity and Muscle–Brain Crosstalk, examined several candidate pathways.
These included muscle-derived metabolites, cathepsin B, FNDC5/irisin, and other signals potentially involved in communication between peripheral tissues and the nervous system.
The review also discussed how exercise can influence kynurenine metabolism.
Kynurenine is a metabolite derived from tryptophan.
Experimental research suggests that exercise-induced changes in skeletal muscle enzymes can alter aspects of kynurenine metabolism.
Some animal studies have linked these changes to stress-related behavioral outcomes.
However, the presence of a plausible molecular pathway does not establish that one myokine directly produces the psychological benefits of exercise in humans.
Exercise affects cerebral blood flow, cardiovascular function, sleep, metabolism, social engagement, and numerous other processes.
The nervous system also adapts to the repeated demands of movement and skill learning.
Muscle-derived signaling may contribute to these effects, but it is only one part of a much larger biological system.
12. Brain-Derived Neurotrophic Factor: Important for Both Neural and Muscular Function
Brain-derived neurotrophic factor, commonly abbreviated BDNF, is involved in neural development, synaptic plasticity, and other neurological functions.
It is particularly well studied in relation to learning and memory.
Research has demonstrated that exercise can influence BDNF-related signaling.
However, BDNF is not produced exclusively within the brain.
The uploaded chapter discusses evidence that skeletal muscle can also express BDNF in response to muscular activity.
Importantly, the authors explain that muscle-derived BDNF may act locally rather than being released in substantial quantities into the circulation.
This distinction matters.
The physiological effects of brain-derived and muscle-derived BDNF are not necessarily interchangeable.
Within skeletal muscle, BDNF-related signaling may participate in local metabolic and regenerative processes.
Within the nervous system, BDNF contributes to other aspects of cellular function.
It is therefore inaccurate to assume that every exercise-induced increase in circulating BDNF originates from muscle or directly indicates enhanced neuroplasticity.
The broader lesson is that the same signaling molecule can perform different functions in different tissues.
13. Bone and Muscle: More Than a Mechanical Relationship
Bone and muscle are closely connected mechanically.
Muscles generate force that is transmitted to bones through tendons.
These forces influence bone loading and contribute to skeletal adaptation.
However, contemporary research reveals that their relationship extends beyond biomechanics.
A 2025 Nature Reviews Endocrinology review, Bone and Muscle Crosstalk in Ageing and Disease, examines biochemical communication among muscle, bone, and adipose tissue.
The authors describe signaling molecules produced by these tissues and their potential roles in growth, repair, and age-related dysfunction.
Exercise can influence this communication through mechanical loading and physiological signaling.
This is relevant because bone and muscle often decline together during aging or prolonged inactivity.
Reduced muscular force may decrease the mechanical stimulus experienced by bone.
At the same time, age-related changes in hormones, inflammation, nutrition, and cellular function can influence both tissues.
Maintaining muscle strength and appropriate skeletal loading is therefore important for physical independence and long-term musculoskeletal health.
14. Muscle–Bone Signaling and Healthy Aging
A 2025 study published in Nature Communications, Exercise-Induced CLCF1 Attenuates Age-Related Muscle and Bone Decline in Mice, investigated an exercise-responsive signaling factor called cardiotrophin-like cytokine factor 1.
The researchers found that circulating CLCF1 levels declined with age but increased following exercise in humans and rodents.
In experimental mouse models, restoring CLCF1 levels was associated with improvements in selected measures of physical performance, glucose regulation, and bone health.
These findings suggest that exercise-related signaling molecules may participate in communication between muscle and bone during aging.
However, the most important therapeutic experiments involved mice.
The study does not establish CLCF1 as an approved or validated treatment for sarcopenia or osteoporosis.
Its significance lies in identifying a potential mechanism that deserves further investigation.
15. Sarcopenia: Why Loss of Muscle Matters Beyond Strength
Sarcopenia involves age-related reductions in muscle strength and other characteristics of skeletal muscle health.
Its consequences can extend beyond difficulty lifting objects or completing exercise.
Reduced muscular function may impair walking speed, balance, mobility, and the ability to perform daily activities.
It is also associated with increased risk of falls, disability, and other adverse outcomes.
The endocrine function of skeletal muscle adds another dimension to this problem.
Loss of muscle tissue and reduced physical activity may change how the body responds to metabolic and inflammatory demands.
However, researchers are still investigating how much of the clinical burden of sarcopenia can be attributed specifically to altered myokine signaling.
The more established evidence supports resistance training, appropriate protein intake, and other individualized interventions that preserve or improve muscular function.
Muscular health should therefore be understood as an important component of healthy aging rather than simply an aesthetic or athletic concern.
16. Exercise and the Immune System
The relationship between physical activity and immunity has received substantial scientific attention.
Regular exercise is associated with improvements in several health outcomes and may influence aspects of inflammatory regulation.
Muscle-derived cytokines participate in some of these processes.
However, exercise also changes immune-cell distribution, blood flow, hormonal signaling, and other physiological factors.
A January 2026 study in Nature Communications, Acute Exercise Rewires the Proteomic Landscape of Human Immune Cells, investigated how a single exercise session influences the molecular characteristics of circulating immune cells.
The findings demonstrated that exercise can produce substantial changes in immune-cell protein expression.
This research reinforces that physical activity represents an immune-regulatory stimulus.
However, changes in immune-cell proteins after exercise do not automatically indicate improved immunity against every disease.
The effects of exercise depend on factors such as intensity, duration, training status, recovery, and underlying health.
The objective is not to maximize immune activation.
It is to support appropriate immune function through sustainable physical activity and broader health practices.
17. Why More Exercise Is Not Always Better
The discovery of myokines can create the impression that greater muscular activity necessarily produces greater health benefits.
However, exercise physiology is governed by the relationship between training stimulus and recovery.
Muscular contractions create mechanical and metabolic demands.
These demands can initiate adaptive signaling.
However, beneficial adaptation requires sufficient recovery and appropriate progression.
Excessive loading can contribute to fatigue, injury, and impaired performance.
Likewise, inadequate energy intake or poor sleep can interfere with training adaptation.
The optimal exercise stimulus depends on the individual's current capacity, medical considerations, goals, and recovery resources.
An older adult beginning resistance exercise does not require the same program as a competitive athlete.
Similarly, an individual recovering from surgery or managing a neurological condition may require modified exercise selection and progression.
The objective is not to generate the largest possible myokine response. It is to provide an appropriate stimulus that produces meaningful improvements in health and function.
18. Aerobic and Resistance Exercise: Different Stimuli, Complementary Benefits
Aerobic exercise and resistance training challenge the body in different ways.
Aerobic exercise commonly emphasizes sustained muscular activity and cardiorespiratory demands.
Resistance exercise emphasizes force production against external resistance.
Both can stimulate metabolic and molecular adaptations.
However, the magnitude and nature of these adaptations vary according to exercise intensity, duration, muscle mass recruited, and other factors.
For example, prolonged endurance exercise can produce substantial increases in circulating IL-6.
Resistance exercise may stimulate pathways relevant to muscle protein synthesis, strength development, and tissue remodeling.
These differences do not mean one exercise type is universally superior.
A comprehensive program can include both forms of training.
Aerobic conditioning supports cardiorespiratory fitness.
Resistance training helps maintain strength, muscular function, and physical capacity.
Balance, coordination, mobility, and task-specific practice may also be relevant.
The most appropriate program combines these elements according to individual needs.
19. The New Science of Exerkines: Beyond Muscle Alone
Although myokines originate from muscle, exercise activates signaling throughout the body.
Researchers increasingly use the broader term exerkines to describe molecules released in response to exercise from multiple organs.
A 2022 review in Nature Reviews Endocrinology, Exerkines in Health, Resilience and Disease, provides a comprehensive overview of these signals.
The authors describe how the heart, liver, adipose tissue, skeletal muscle, nervous system, and other tissues release molecules in response to exercise.
Examples include cardiokines from the heart, hepatokines from the liver, and myokines from skeletal muscle.
These molecules may act locally or influence distant tissues.
Some are transported through extracellular vesicles.
Extracellular vesicles are small membrane-bound structures that can carry proteins and other molecular cargo between cells.
However, the presence of exercise-responsive molecules in circulation does not necessarily establish their source or function.
A signaling molecule may be released by several tissues or have different effects depending on its biological context.
The emerging field therefore requires careful investigation of where signals originate, which cells respond, and whether the effects meaningfully contribute to exercise adaptations.
20. What the Latest Molecular Research Reveals About Exercise
An October 2026 Nature Metabolism study, Systemic Proteomic Dynamics of Acute Exercise Reveal Genetic Links to Health and Disease, illustrates how rapidly this field is developing.
Researchers used advanced proteomic methods to investigate exercise-related changes in thousands of proteins.
They examined biological responses across plasma, saliva, and urine.
Their findings identified numerous exercise-responsive proteins and demonstrated that different biological compartments exhibit distinct molecular patterns over time.
The investigators also identified differences associated with exercise modality and biological characteristics.
Their analyses suggested that acute exercise stimulates coordinated changes involving immune activity, tissue remodeling, molecular transport, and metabolic regulation.
Importantly, these responses evolve during recovery.
The molecular environment immediately after exercise differs from that observed several hours later.
This provides a more dynamic understanding of exercise adaptation.
Rather than producing one uniform hormonal response, physical activity initiates multiple interacting processes that change across time.
However, the study does not establish that measuring thousands of circulating proteins improves exercise prescription in routine clinical care.
It provides a scientific foundation for generating and testing future hypotheses.
21. Why Muscle Health Matters for Chronic Disease Prevention
Physical inactivity is associated with increased risk of numerous chronic diseases.
Regular physical activity can help improve blood pressure, glucose regulation, cardiorespiratory fitness, physical function, and several other health outcomes.
The discovery of myokines provides potential molecular explanations for some of these benefits.
However, the clinical importance of exercise does not depend on proving that every benefit is mediated through myokines.
Exercise also influences mechanical loading, vascular adaptation, autonomic regulation, energy expenditure, and numerous other pathways.
Some benefits are directly supported by large clinical trials and long-term population studies.
Others are suggested primarily by experimental mechanisms.
These levels of evidence should be distinguished.
For example, resistance training is well supported for improving muscular strength.
Aerobic exercise is well supported for improving cardiorespiratory fitness.
By contrast, attempting to increase one specific myokine as a treatment for an unrelated disease may remain experimental.
The goal of clinical exercise prescription should be to improve meaningful patient outcomes rather than optimize an isolated molecular marker.
22. Why Movement Quality Still Matters
Understanding muscle's endocrine role does not eliminate the importance of biomechanics.
Muscles must be able to generate and tolerate force during activities appropriate to the individual.
Movement limitations, persistent pain, weakness, or reduced coordination can interfere with exercise participation.
For example, someone experiencing recurrent knee pain may be unable to tolerate certain forms of resistance training.
An individual with poor balance may require additional support before participating safely in more demanding exercises.
A person recovering from a concussion or managing a neurological condition may need a more individualized progression.
In such cases, movement assessment and rehabilitation can help identify appropriate starting points.
However, movement screening should not be interpreted as a test of myokine function.
Likewise, correcting a movement pattern does not automatically produce a specific endocrine outcome.
The connection is more practical.
Improving movement capacity may help individuals participate in sufficient physical activity to obtain its broader physiological benefits.
23. Why Exercise Should Be Prescribed, Not Merely Recommended
Healthcare professionals commonly encourage patients to become more physically active.
Although this advice is appropriate, it may not provide enough information to support meaningful behavior change.
A person may understand that exercise is beneficial but remain uncertain about which activities to perform, how frequently to train, or how to progress safely.
These questions become especially important when someone has chronic pain, physical limitations, deconditioning, or medical complexity.
Individualized exercise prescription considers the person's current capabilities and goals.
It also accounts for exercise selection, intensity, volume, frequency, progression, and recovery.
The objective is to develop a program that is effective, practical, and sustainable.
This approach recognizes that the physiological benefits of exercise depend on actual participation over time.
A scientifically sophisticated explanation of myokines is useful, but it cannot replace a realistic training plan.
24. How This Research Informs Move Well
We recognize that movement is fundamental to human health.
The benefits of physical activity extend beyond musculoskeletal function.
Exercise influences metabolism, cardiovascular regulation, inflammatory pathways, neurological function, and numerous other physiological systems.
The emerging science of myokines and exerkines provides a valuable explanation for how working muscles participate in communication throughout the body.
Within our Move Well philosophy, we emphasize comprehensive movement assessment, appropriate exercise prescription, and individualized rehabilitation strategies.
Depending on the individual's needs, this may involve functional movement screening, chiropractic care, physiotherapy, corrective exercise, strength and conditioning, or other relevant interventions.
We also recognize the importance of integrating physical capacity with broader health considerations.
For some individuals, the primary goal is restoring movement following injury.
For others, it is maintaining muscular strength and independence during aging.
Athletes may require more advanced programs designed to support performance and long-term physical development.
Individuals managing chronic medical conditions may need exercise prescriptions adapted to their symptoms and clinical circumstances.
However, the discovery of muscle-derived signaling molecules does not mean that any particular chiropractic technique, movement screen, or corrective exercise has been proven to optimize endocrine function.
Nor do we claim to diagnose myokine deficiencies through routine commercial laboratory testing.
Our approach focuses on established functional outcomes while remaining informed by emerging scientific mechanisms.
These outcomes may include improvements in strength, endurance, balance, exercise tolerance, movement confidence, and overall physical capacity.
The goal is not simply to move more.
It is to help individuals develop the capacity to engage in meaningful physical activity safely and sustainably.
Conclusion: Movement Is a Biological Conversation
The discovery that skeletal muscle functions as an endocrine organ represents an important development in exercise science.
For decades, muscle was understood primarily through its mechanical and metabolic functions.
We now recognize that contracting muscles also generate signals capable of influencing other tissues.
These signals participate in interactions involving glucose regulation, lipid metabolism, immune activity, muscular adaptation, and potentially neurological health.
Newer research has expanded this concept beyond skeletal muscle to include communication among multiple organs during exercise.
This broader network of exerkines helps explain why physical activity produces such diverse physiological effects.
However, many individual signaling pathways remain under investigation.
The strongest clinical evidence still supports appropriately prescribed, sustainable physical activity rather than attempts to manipulate isolated molecules.
Exercise is not merely a way to strengthen the body. It is one of the fundamental physiological stimuli through which the body coordinates its metabolism, maintains its functional capacity, and adapts to changing demands.
We believe this understanding reinforces the importance of comprehensive movement care.
The objective is not simply to improve how someone moves during an examination.
It is to help them develop the strength, mobility, coordination, endurance, and confidence necessary to participate in the physical activities that support long-term health.
Your muscles do more than move you. Through movement, they help communicate with and regulate the rest of your body.
Research References
Legård GE, Pedersen BK. Muscle as an endocrine organ. In: Muscle and Exercise Physiology. Elsevier; 2019. Chapter 13. https://doi.org/10.1016/B978-0-12-814593-7.00013-X
Chow LS, Gerszten RE, Taylor JM, et al. Exerkines in health, resilience and disease. Nature Reviews Endocrinology. 2022;18:273–289. https://doi.org/10.1038/s41574-022-00641-2
Kistner TM, Pedersen BK, Lieberman DE. Interleukin 6 as an energy allocator in muscle tissue. Nature Metabolism. 2022;4:170–179. https://doi.org/10.1038/s42255-022-00538-4
Pedersen BK. Physical activity and muscle–brain crosstalk. Nature Reviews Endocrinology. 2019. https://doi.org/10.1038/s41574-019-0174-x
Kirk B, Lombardi G, Duque G. Bone and muscle crosstalk in ageing and disease. Nature Reviews Endocrinology. 2025;21:375–390. https://doi.org/10.1038/s41574-025-01088-x
Molecular insights of exercise therapy in disease prevention and treatment. Signal Transduction and Targeted Therapy. 2024. https://doi.org/10.1038/s41392-024-01841-0
Exercise-induced CLCF1 attenuates age-related muscle and bone decline in mice. Nature Communications. 2025;16:4743. https://doi.org/10.1038/s41467-025-59959-w
Walzik D, Joisten N, Metcalfe AJ, et al. Acute exercise rewires the proteomic landscape of human immune cells. Nature Communications. 2026. https://doi.org/10.1038/s41467-025-68101-9
Systemic proteomic dynamics of acute exercise reveal genetic links to health and disease. Nature Metabolism. Published October 2026. https://doi.org/10.1038/s42255-026-01621-w
Rai M, Demontis F. Therapeutic potential of myokines and myometabolites for brain ageing and neurodegeneration. Nature Reviews Endocrinology. Published online October 2025. https://doi.org/10.1038/s41574-025-01195-9
Chen X, Zhang G, Liu M, et al. New perspectives on molecular mechanisms underlying exercise-induced benefits in Parkinson's disease. npj Parkinson's Disease. 2025;11:256. https://doi.org/10.1038/s41531-025-01113-w
Hawley JA, Hoffman NJ. Twenty years of progress in human exercise metabolism research. Nature Reviews Endocrinology. 2025;21:658–659. https://doi.org/10.1038/s41574-025-01181-1
Rose-John S, Jenkins BJ, Garbers C, et al. Targeting IL-6 trans-signalling: past, present and future prospects. Nature Reviews Immunology. 2023;23:666–681. https://doi.org/10.1038/s41577-023-00856-y