Joint, Muscle and Bone Health
Movement is not just something your body does. It is one of the ways your body heals itself.
Most people think muscles move bones, bones hold you up and joints let you bend. That is true and it is a small part of the story. Muscle, bone and connective tissue behave like an enormous communication network. Every time you move, your muscles release signalling molecules, your bones release hormones, and your joints respond to changing load. Those signals reach inflammation, metabolism, the brain, the immune system and the way you age.
Begin reading
What one walk sets off
Movement, meaning muscles contract
Myokines released, hundreds of signalling molecules
Inflammation falls across the whole body, not just in muscle
Blood sugar improves as insulin starts working better
Mitochondria multiply, adding capacity to make energy
Brain, bone and gut all receive the signal
There is no pill that reproduces what a working muscle releases. Movement is not exercise. It is biology.
Almost every page about joints is about arthritis. Almost every page about muscle is about strains. Almost every page about bone is about calcium. All three treat the musculoskeletal system as scaffolding that wears out. The research of the last two decades says something considerably more interesting: it is one of the largest endocrine and immune organs you have, and it is actively regulating the rest of you every time it works.
The musculoskeletal system is not simply the body that moves you. It is one of the body’s largest healing organs.
This page covers what a contracting muscle actually releases and where those signals go, why bone is living tissue that talks to metabolism and the brain, why joint health is a balance between what builds tissue and what breaks it down, why sitting is its own risk even in people who train, what muscle loss really costs, why joint pain is so rarely only about the joint, and what is worth measuring before anyone reaches for a supplement.
The central claim
There is no nutraceutical that reduces inflammation as effectively as exercise does.
Which is inconvenient for everyone selling one, including anyone in functional medicine.
Free guide
You Are Not Wearing Out
A structured walk through what actually builds tissue and what breaks it down, the simple strength and protein numbers that preserve muscle through the decades, which markers are worth measuring before supplements, and how to keep moving when something already hurts.
You Are Not Wearing Out
Why movement is one of the ways the body heals itself.
The finding that reframes everything
Muscle is one of your largest healing organs.
For most of the last century we understood skeletal muscle as a machine for generating force. That understanding is now clearly incomplete. Contracting muscle produces and secretes hundreds of signalling molecules, called myokines, which travel in the bloodstream and act on tissues all over the body.
What they influence is not a modest list. Myokines are involved in the regulation of chronic pain, mood, sleep, insulin sensitivity, fatigue, cognition, bone remodelling and the integrity of the intestinal lining. Muscle is not the only organ doing this either. Bone releases its own signals during movement, as do the liver, the heart, the brain and the gut community. The collective name for all of them is exerkines, and they are the reason physical activity improves outcomes in conditions that have nothing obvious to do with muscles.
This is why the single most useful thing a clinician can establish is whether someone is able to move regularly. If they can, the odds of a good outcome improve across almost every chronic condition on this site. If they cannot, everything else gets harder.
Exercise does not only strengthen muscle. It changes the chemistry of the whole body.
Signals released by movement
From more than one organ
Signals released by movement
Who is talking
Muscle sends myokines
Bone sends osteokines, including osteocalcin
The liver, heart and brain send their own signals too
The gut community answers with short chain fatty acids
What myokines help regulate
Chronic pain, mood and sleep
Insulin sensitivity and fatigue
Cognition and nerve health
Bone density and the integrity of the gut lining
No pill reproduces this list, which is why physical activity improves outcomes in conditions that appear to have nothing to do with muscle.
Where the signals actually land
A contracting muscle is talking to everything.
This is the part that changes how you read the rest of this site. When you walk, lift something heavy or climb a flight of stairs, the molecules your muscles release do not stay in your legs. They reach the brain, the immune system, the pancreas, the bones, the gut community and the machinery inside your cells that makes energy. Movement is an intervention that acts on all of them at once.
One organ, talking to all of these
Brain
Immune system
Blood sugar
Mitochondria
Bones
Gut
Mood
Inflammation
Recovery
Longevity
Stop the muscle working and every one of these loses an input it was relying on, which is why an injury that reduces activity so often ends up looking like a metabolic or mood problem months later.
The gut connection deserves a specific mention because it surprises people. Physical inactivity reduces the diversity of the gut microbiome independently of diet, and physical activity improves it, again independently of diet. Athletes carry more diverse gut communities and produce short chain fatty acids more efficiently than sedentary people eating similarly. The relationship also runs the other way, since the gut community influences muscle protein synthesis and mitochondrial function. Gut Health covers that system, and Brain Health covers where several of these signals end up.
Not a frame, an organ
Bone is alive, and it is talking back.
Bone is not an inert frame holding you together. It is living tissue that is broken down and rebuilt continuously throughout life, and during that rebuilding it releases hormones of its own. For fifty years the skeleton was understood as something hormones acted upon. Only recently has it become clear that the skeleton answers.
The best studied of those signals is osteocalcin, released by bone building cells during remodelling. It influences insulin sensitivity and how insulin is released, contributes to testosterone production, and appears to matter for the brain. Which means declining bone volume is not only a fracture problem. Fewer bone building cells means less of that signal reaching everything it used to reach.
There is a second consequence that almost nobody is told about. Heavy metals such as lead and cadmium carry a similar charge to calcium and get incorporated into bone during remodelling, where they can sit for decades. When bone is lost at speed, some of that stored load is released back into circulation. Blood lead levels rise measurably in women after menopause for exactly this reason, which is a real clinical consideration rather than a curiosity.
Healthy bone supports healthy physiology. Losing it costs far more than fracture risk.
Bone as an endocrine organ
What it sends, and what is lost
Bone as an endocrine organ
What bone releases
Osteocalcin, produced during bone remodelling
It influences insulin sensitivity
And how efficiently insulin is released
And testosterone production
And the health of the brain
What losing bone costs
Fewer bone building cells
Less of that signal reaching circulation
Metals stored in bone released back out during rapid loss
Fracture risk, and a good deal more besides
Bone is not scaffolding. Osteoporosis also has no symptoms at all until something breaks, which is why imaging rather than how you feel is what identifies it.
The most useful idea on this page
Tissue health is a balance, not a countdown.
Every tissue in the musculoskeletal system is being built up and broken down at the same time, continuously. Whether it holds up over decades depends on which side is winning. That is a considerably more useful model than wear and tear, because one of those two columns is largely under your influence and the other is often treated as fate.
The equation that decides tissue health
What breaks tissue down
Sedentary time
Insulin surges
Body composition at either extreme, too high or too low
Chronic inflammation
Microbiome disturbance and a permeable gut lining
Chemical exposure, and impaired ability to clear it
What builds it back
Movement, and the signals it releases
Adequate protein
Sleep, when the repair hormones are released
Hormones, including thyroid, testosterone and oestrogen
Nutrients that cartilage and bone are actually built from
Regenerative injection therapies where they are indicated
When what builds tissue outweighs what breaks it down, tissue holds up. When it does not, tissue deteriorates whatever else is being taken. If a supplement is not working, the load against it is usually winning.
That last line is worth sitting with, because it reframes a common experience. When someone with joint degeneration takes a well chosen supplement for three months and nothing happens, the usual conclusion is that the supplement does not work. Often the more accurate conclusion is that the deteriorative side of the equation is simply larger. Unstable blood sugar, a sedentary day, poor sleep and ongoing inflammation will comfortably outweigh anything in a capsule, and no amount of raw material fixes a demolition problem. Chronic Inflammation and Blood Sugar and Metabolic Health cover the two largest entries in that left hand column.
Age matters. It is not the whole story.
Your joints reflect more than wear and tear.
A healthy joint needs four things working together: the cells that build cartilage, a matrix that holds water for shock absorption, collagen for structure, and synovial fluid for lubrication. Cartilage also has no blood supply of its own, which is the fundamental clinical problem in joint disease and the reason it repairs so slowly.
Joints deteriorate along two routes, and most people have some of both. The first is abnormal load on healthy tissue: an old injury, an altered gait, an unstable joint, a movement pattern that puts force somewhere it was not designed to go. The second is normal load on unhealthy tissue: systemic inflammation, unstable blood sugar, low muscle mass and therefore fewer of those repair signals. The single largest driver of progression is continued loading of a joint that is not moving correctly, which is why how you move matters as much as what you take.
One honest limit belongs here. Cartilage that has already been lost does not generally grow back, and no page should imply otherwise. What is genuinely modifiable is the rate of further loss, the inflammatory load around the joint, the strength of the muscle supporting it, and how much the joint can tolerate day to day. Those are worth a great deal, and they are a different promise from reversal.
The question is not only how damaged the joint is. It is what is still being done to it.
How joints actually fail
Two routes, usually both
How joints actually fail
What a healthy joint needs
Chondrocytes, the cells that build cartilage
A matrix that attracts and holds water for shock absorption
Collagen for structural integrity
Synovial fluid for lubrication and friction reduction
Two routes to failure
Abnormal load on healthy tissue, from injury, gait or instability
Normal load on unhealthy tissue, from inflammation, blood sugar or lost muscle
Most people have some of both
Cartilage has no blood supply of its own, which is why it repairs so slowly and why reducing what is still damaging it matters more than any single supplement.
Where the symptom appears, and where it began
Joint pain is rarely just about the joint.
Pain in a knee is information about a knee and about a good deal else. The joint is where the symptom shows up. The biology producing it frequently starts elsewhere, in the systems that decide how much inflammation is circulating, how well tissue can repair itself, and how much load is landing on that joint every day.
What is actually feeding the pain
Biomechanics
Inflammation
Blood sugar
Nutrition
Muscle mass
Sleep
Hormones
Gut health
Environment
Body composition
The joint is where you feel it. Several of these decide how much you feel, which is why two people with similar imaging can have very different amounts of pain.
One distinction is worth knowing before any of this, because it changes the whole approach. Osteoarthritis usually produces pain in a joint that was injured or overloaded, often one or two joints rather than many. Autoimmune arthritis produces pain across many joints, frequently symmetrically, and it involves the immune system attacking joint tissue rather than the tissue simply wearing. They need different investigation and different treatment, and the pattern of which joints hurt is the first clue. If many joints hurt at once, particularly with morning stiffness lasting more than an hour, that warrants proper rheumatology assessment rather than a lifestyle plan.
On what a scan can and cannot tell you
Two people with almost identical imaging can have completely different amounts of pain. The difference is rarely in the picture.
It is usually in the inflammation, the muscle and the load.
The inputs that decide the balance
What actually determines how tissue holds up.
None of these is exotic. Most of them are things that get treated as background conditions of life rather than as clinical variables, which is precisely why they are so often left unaddressed while everyone concentrates on the joint that hurts.
The intervention with the widest reach
Physical activity improves microbiome diversity, stimulates the creation of new mitochondria, activates repair hormones, dampens systemic inflammation, improves how insulin works and supports circulation. Nothing else on this list does all of that at once.
A reservoir as well as an engine
Muscle is where a great deal of glucose is handled, where amino acids are stored for emergencies, and where the signals that regulate inflammation are produced. Losing it removes a buffer that everything else was quietly using.
The raw material, and usually short
The official minimum prevents deficiency rather than building anything. Among older adults, those eating the most protein lost substantially less lean mass than those eating the least, and intake spread across meals works better than one large serving.
When the building actually happens
Growth hormone is released mostly in deep sleep, testosterone falls with sleep deprivation and cortisol rises, which shifts the body toward breakdown. Consistently sleeping under six hours is independently associated with a higher risk of muscle loss.
Insulin surges damage tissue directly
Repeated insulin surges activate fat tissue to release inflammatory signals, which in turn increase the activity of the cells that break bone down. This is also why gout flares can happen without any change in diet. Blood Sugar and Metabolic Health
It attacks all three tissues at once
In muscle it causes loss of endurance and slow recovery, in bone it activates the cells that resorb it, and in joints it accelerates degeneration. It also impairs mitochondria everywhere, not only in muscle. Chronic Inflammation
The most consistent single finding here
In one study of a hundred and twenty people with myofascial pain, not one reached the ideal range and around eight in ten were insufficient or deficient. It affects protein synthesis, mitochondrial function and muscle strength, and it is trivial to measure.
Repeatedly low in chronic muscle pain
People with long standing myofascial pain show significantly lower magnesium, B12, zinc, selenium and folate than controls, alongside lower total antioxidant capacity and higher oxidative stress. Worth measuring rather than guessing. Nutrient Deficiencies
Thyroid, testosterone and oestrogen
Low thyroid function produces muscle pain and weakness in a large share of people who have it, oestrogen loss at menopause drives accelerated bone loss, and testosterone builds bone and muscle in both sexes. Hormone Health
Bidirectional, and increasingly well documented
Gut permeability markers are raised in inflammatory joint disease and track with how active it is, and the gut community appears to influence cartilage health independently of diet or body weight. It also affects muscle protein synthesis. Gut Health
Both directions, not just one
Excess fat tissue releases inflammatory signals that increase bone resorption and joint damage. Being underweight is an independent risk factor for osteoporosis. The problem is the extreme rather than the direction.
Whether repair can keep up at all
Everything above assumes the body can still rebuild. When recovery itself has failed, adding training load makes things worse rather than better, and the sequence has to change. Chronic Fatigue and Pain
The finding people least want to hear
You cannot train your way out of sitting.
The common assumption is that an hour in the gym buys off the other fifteen hours. The research does not support it. Prolonged sedentary time is associated with worse outcomes independently of how much moderate or vigorous activity someone does, and independently of body weight and blood sugar control.
The markers move in a measurable way. Across three thousand adults, daily sitting time and television viewing were positively associated with inflammatory markers regardless of leisure time exercise. The same relationship appears in children. Sedentary behaviour also appears to heighten stress reactivity across blood pressure, inflammatory and cortisol responses, which is one proposed route from sitting to cardiovascular disease.
The practical consequence is not that structured exercise stops mattering. It is that the two are separate variables and both need attention. Frequent interruption of sitting through the day appears to do something that a single longer session does not, which is a considerably easier thing to change than most clinical advice.
Sitting is not the absence of exercise. It is its own input, with its own effects.
Sitting as its own variable
Not simply missing exercise
Sitting as its own variable
What sitting does
Raises inflammatory markers measurably
Independently of how much you train
Independently of body weight
And independently of blood sugar control
What actually helps
Breaking it up frequently through the day
Standing and walking between periods of sitting
Rather than one longer workout to compensate
You cannot train it off. Sitting is not simply the absence of exercise, it is its own input with its own effects, which means both variables need attention.
The condition almost nobody is screened for
Muscle loss changes everything downstream.
From somewhere around the fourth decade, most adults lose roughly three to five percent of muscle mass per decade unless they actively defend it. Over a lifetime most men lose about a third of what they had. The name for this is sarcopenia, and its consequences reach far past being weaker.
The numbers are worth stating plainly. Sarcopenia is associated with substantially higher mortality across populations and definitions, and with roughly one and a half to three times the risk of falls. It also removes an entire reservoir the body was drawing on: less muscle means fewer myokines, so more systemic inflammation, less well regulated blood sugar, impaired temperature control and reduced growth factor availability for healing anything else.
This is also a genuine blind spot in ordinary care. It is not routinely screened for, most clinicians are not confident treating it, and it has no dramatic moment that triggers investigation. It simply happens quietly across two decades until the day someone cannot get out of a chair without using their arms.
Maintaining muscle is one of the strongest investments available in how the second half of life goes.
What muscle loss costs
Beyond being weaker
What muscle loss costs
What is lost, and when
Roughly three to five percent per decade after thirty
Most men lose about thirty percent across a lifetime
Unless it is actively defended
What that costs
One and a half to three times the risk of falls
Substantially higher mortality across populations
Fewer myokines, and therefore more systemic inflammation
Weaker immune function and slower healing of everything else
Almost nobody is screened for this, it is not routinely treated, and it happens quietly across two decades rather than arriving as an event.
Specific, and not complicated
What actually preserves muscle and bone.
There is reasonable agreement on the numbers here, which is unusual in this field. The difficulty is not knowing what to do. It is that the requirements are unglamorous, they have to be sustained for years rather than weeks, and they get progressively harder to meet with age because the body becomes less responsive to the same stimulus.
The requirements, plainly
With age the same stimulus produces less response, from exercise, from protein and from hormones alike. Which is an argument for starting earlier rather than a reason to conclude it is too late.
Two practical notes. Walking is genuinely useful and on its own it does not appear to increase bone density, though it does limit further loss, so it belongs alongside resistance work rather than instead of it. And on supplements, the honest position is that creatine monohydrate is the one compound with reasonable evidence for helping build muscle and strength, at around three to five grams a day. Everything else in this area is supportive at best. Longevity covers why muscle and recovery keep appearing as the strongest predictors of how the later decades go.
Order before breadth
How an evaluation is sequenced.
Rather than treating muscle, bone and joint as isolated structures, the evaluation looks at the systems that decide whether they can repair themselves. It starts with the story and with watching someone move, because both are free and both frequently relocate the problem away from where it hurts.
The order we work in
Which kind of arthritis it is changes everything that follows, and it is answered by the pattern and the bloods rather than by a supplement trial.
On bone specifically, there is no way around imaging. Osteoporosis produces no symptoms at all until something fractures, so density scanning is what identifies it, and bone turnover markers are what let you see whether anything is changing between scans rather than waiting two years to find out. Comprehensive Blood Chemistry covers the foundation, Micronutrient Testing covers status where the diet or absorption is in question, and Functional Medicine Testing explains how the specialised options fit together.
The sequence
How I approach joint, muscle and bone problems.
This describes a clinical process carried out with a person rather than a protocol to run on yourself. It works alongside rheumatology, orthopaedics and physical therapy rather than in place of any of them, and it assumes that anything structural stays with the people who handle structural problems.
Supply the raw materials second. Stop the demolition first.
Do not wait on these
Some of this is not a long game.
Almost everything on this page concerns years. The following are different. They need prompt medical assessment on the day rather than a plan, and a couple of them are genuine emergencies where hours matter.
A hot, red, swollen joint, particularly alongside fever
Back pain with numbness in the saddle area, or new bladder or bowel changes
Progressive weakness or numbness in an arm or leg
A joint that cannot take weight at all after an injury
Bone pain that is worse at night or at rest
New severe back pain over fifty, or with any history of cancer
Unexplained weight loss alongside bone or joint pain
Calf pain with swelling and warmth
Joint pain with a rash, mouth ulcers or eye inflammation
Sudden loss of function after a pop or snap
Loss of height, or a new curve in the spine
Many joints swelling at once with prolonged morning stiffness
Two deserve naming directly. A single hot, swollen, exquisitely painful joint with fever can be an infected joint, which destroys cartilage within days and needs assessment the same day rather than the same week. And back pain accompanied by numbness around the groin or saddle area, or by new difficulty controlling the bladder or bowel, is a surgical emergency. Neither of these is common. Both are worth recognising immediately.
Free guide
Stop the demolition before you buy the bricks
You Are Not Wearing Out covers what actually builds tissue and what breaks it down, the strength and protein numbers that preserve muscle through the decades, which markers are worth measuring before any supplement, and how to keep moving when something already hurts.
Own your biology
Movement is a signal, not a chore.
Your musculoskeletal system is not simply how you move through life. It is one of the systems that helps you recover from it. Healthy muscle communicates with your brain, healthy bone influences your metabolism, and movement itself regulates inflammation more effectively than anything you can buy.
Which reframes the goal. Reducing pain matters and you should do it. But the larger aim is restoring one of the body’s biggest repair systems to working order, so that it can go back to doing what it was doing quietly in the background for everything else. Walk more often than you think you need to. Lift something heavy twice a week. Eat enough protein. Sleep. Break up the sitting. None of it is exciting and all of it is chemistry.
Organ from scaffolding Muscle and bone are endocrine tissue, not just structure.
Balance from countdown Tissue health is what builds versus what breaks down.
Load from age Continued loading of a poorly moving joint drives most progression.
Signal from exercise Movement is biology, and there is no pill that copies it.
Bring the whole picture, not just the joint.
No pressure, and nothing to buy. Bring which joints are involved and for how long, any injury history, any imaging or rheumatology results you already have, what a real week of movement and sitting looks like, recent blood work, everything you take including anti inflammatories, and what you have already tried.
Common questions
Questions about joints, muscle and bone.
Short, plain answers to what people ask most.
Is joint pain just part of getting older?
Can lost cartilage grow back?
Do glucosamine and chondroitin actually work?
What about cortisone injections?
I exercise for an hour a day. Is that enough?
How much protein do I actually need?
Does dairy prevent osteoporosis?
I have gout. Is that not about diet?
I am in pain. How am I supposed to exercise?
