For many years, muscle was viewed simply as the tissue responsible for movement. Build bigger muscles, become stronger and improve athletic performance, that was the common understanding.
Modern science has completely changed that perspective.
Researchers now recognise skeletal muscle as one of the body’s largest and most influential organs. Beyond helping you lift weights or climb the stairs, muscle actively communicates with nearly every major system in the body. It produces signalling molecules called myokines, helps regulate blood sugar, protects bone health, supports immune function, influences brain health and plays a significant role in healthy ageing.
This shift has transformed the way exercise professionals view resistance training.
As a Personal Trainer in Hertfordshire, I spend much of my time helping clients understand that strength training isn’t simply about aesthetics. Whether I’m working with someone in St Albans, Harpenden, Hertford, Hitchin, Hatfield, Stevenage, Ware or the surrounding areas, my goal is always the same: build stronger, healthier people for life.
If there was a medication capable of delivering many of the benefits associated with healthy muscle tissue, it would almost certainly become one of the most prescribed drugs in the world. Fortunately, that “medicine” already exists, and it’s called resistance training.
What Is Skeletal Muscle?
Skeletal muscle accounts for approximately 30–40% of total body weight in most healthy adults, making it the largest organ system in the human body.
Every movement you perform relies on skeletal muscle.
Walking the dog.
Standing from a chair.
Carrying shopping.
Playing with your children.
Climbing stairs.
Maintaining good posture.
Recovering from illness.
Even breathing depends on specialised skeletal muscles.
However, muscle isn’t simply a mechanical engine. It is a highly active metabolic tissue that constantly adapts to your lifestyle. When you challenge it through resistance training, muscle becomes stronger, more efficient and more resilient. When it is neglected through inactivity, it gradually shrinks, a process known as sarcopenia.
This loss doesn’t simply reduce strength.
It increases the risk of falls, fractures, insulin resistance, reduced independence and poorer long-term health.
Muscle Is an Endocrine Organ
Perhaps the most exciting discovery in exercise science during the past two decades is that skeletal muscle functions as an endocrine organ.
This means that contracting muscles release hundreds of chemical messengers known as myokines into the bloodstream.
These myokines travel throughout the body, influencing numerous organs including:
* The brain
* The liver
* The heart
* Bones
* Fat tissue
* The immune system
* Blood vessels
Rather than viewing exercise as something that only strengthens muscles, researchers now understand that muscle contraction triggers a cascade of beneficial biological effects throughout the entire body.
Every workout becomes a signal telling your body to become healthier.
Myokines: The Body’s Internal Pharmacy
Think of myokines as your body’s own internal communication network.
Whenever muscles contract during resistance training, cycling, brisk walking or other forms of exercise, they release proteins that help coordinate positive adaptations across multiple organs.
Research suggests myokines may help:
* Improve insulin sensitivity.
* Reduce chronic low-grade inflammation.
* Support healthy immune function.
* Improve blood vessel health.
* Encourage healthy fat metabolism.
* Promote brain function.
* Support healthy ageing.
This helps explain why regular exercise consistently reduces the risk of so many chronic diseases.
The benefits are not isolated to muscles alone, they ripple throughout the body.
Muscle Is Your Metabolic Engine
One of the most important roles of skeletal muscle is helping regulate blood glucose.
After eating carbohydrate-containing foods, glucose enters the bloodstream. Skeletal muscle acts as the body’s largest storage site for glucose by converting it into glycogen.
The healthier and more active your muscles are, the more effectively they can remove glucose from the bloodstream.
Resistance training also improves insulin sensitivity, allowing your body to use insulin more efficiently.
This is one reason why both resistance exercise and aerobic exercise are recommended for reducing the risk of developing type 2 diabetes.
For people who spend much of the day sitting, preserving muscle mass becomes even more important.
Loss of muscle often means poorer glucose control.
Maintaining muscle usually means better metabolic health.
Muscle Helps Protect Your Brain
Exercise doesn’t just change your body, it changes your brain.
During exercise, muscles release myokines that are thought to influence brain function and cognitive health.
Research continues to investigate how exercise may support:
* Learning.
* Memory.
* Mood.
* Cognitive performance.
* Healthy brain ageing.
Regular physical activity has also been associated with a lower risk of cognitive decline later in life.
While no single exercise programme can guarantee protection against neurological disease, maintaining muscle through regular resistance training appears to be one of the most powerful lifestyle habits available.
Strong Muscles Support Strong Bones
Bone is living tissue
Like muscle, it constantly adapts to the demands placed upon it.
Resistance training places healthy mechanical stress on bones, encouraging them to maintain or improve their density over time.
This becomes increasingly important after the age of 40, when gradual losses in bone mineral density begin to accelerate.
For many adults, building muscle is one of the most effective ways to help protect the skeleton as they age.
Muscle and bone work together
Improve one, and you often improve the other
