Why muscle is one of the biggest keys to healthy aging!
We know that a healthy muscle mass keeps us strong.
And in our series Rebuilding Mum & Dad, my parents proved it can also keep you mobile and independent throughout later life.
Most of us are also now beginning to understand that when we build/maintain muscle we also build/maintain bone density. My mum improved her spinal bone density by 7% aged 82 by lifting weights.
But what is way less known is muscle is key to staying healthy.
That’s because it’s a major player in our metabolic health.
Poor metabolic health is closely linked with age-related chronic conditions including type 2 diabetes, fatty liver disease, heart disease, frailty and even dementia.
What is metabolic health?
When we talk about metabolic health, we’re really talking about how well the body creates, stores and uses its energy.
In other words it’s about how your body runs its fuel systems including managing things like blood sugar, fats and cholesterol.
A metabolically healthy body:
- Keeps blood sugar within a healthy range
- Uses insulin efficiently
- Handles fats and cholesterol well
- Maintains steady energy levels
- Stores less fat around vital organs
Muscle isn’t just for movement — it’s a metabolic organ
We tend to think of muscle as something that helps us walk, lift, and stay mobile. But metabolically, muscle behaves more like an organ than a simple tissue.
It actively influences blood sugar regulation, insulin sensitivity, fat metabolism, inflammation and resting metabolic rate.
This is why muscle mass is now recognized as one of the strongest predictors of long-term metabolic health.
Muscle acts as the body’s main glucose store
After we eat carbohydrates, glucose enters the bloodstream. That glucose needs somewhere to go.
Muscle is the primary destination.
Muscle cells absorb glucose and store it as glycogen, ready to be used for movement and daily activity. The more muscle you have, the more storage capacity you have!
This matters because excess glucose lingering in the blood drives insulin resistance and insulin resistance drives age-related disease.
Muscle improves insulin sensitivity — even without weight loss
One of muscle’s most powerful effects is how it improves insulin sensitivity.
Insulin acts like a key, unlocking cells so glucose can enter.
Trained muscle becomes more responsive to that signal, meaning less insulin is needed to do the same job.
Muscle contraction pulls glucose into cells.
This happens independently of insulin and is why resistance training is so effective for people with pre-diabetes, type 2 diabetes and menopausal metabolic changes.
And when you improve insulin sensitivity you reduce your risk of a whole host of nasty diseases, including dementia.
Muscle raises your resting metabolic rate
Muscle uses energy around the clock, not just during exercise.
As muscle mass increases, baseline energy expenditure rises, fat gain becomes less likely over time and it becomes easier to maintain your weight.
Muscle improves how the body handles fat
Healthy muscle plays a key role in fat metabolism, clearing fats from the bloodstream more efficiently.
It improves triglyceride levels (a type of fat in the blood linked to heart disease when elevated) and HDL cholesterol (the “good” cholesterol that helps remove excess fat from the bloodstream), and reduces fat storage in organs such as the liver.
Low muscle mass, by contrast, is associated with higher levels of visceral fat — the type most closely linked to metabolic disease.
Muscle is also a powerful signalling tissue
When muscles contract, they release chemical messengers known as myokines.
These signals improve insulin sensitivity in other tissues, reduce chronic inflammation and support brain and immune health.
In other words, muscle doesn’t just benefit itself — it sends protective signals throughout the body.
Why muscle becomes even more important as we age
From our 30s onwards, we begin to lose muscle mass unless we actively challenge it.
This gradual loss reduces glucose storage capacity, worsens insulin resistance, makes it easier to gain fat and weakens our metabolic health.
This explains why two people of the same weight can have vastly different metabolic health outcomes.
Muscle protects metabolic health independently of body weight.
The bottom line
If there’s one message worth taking away, it’s this:
Muscle is the body’s metabolic shock absorber — the more you have, the better your system copes.
Building and maintaining muscle isn’t about aesthetics or chasing youth. It’s about preserving independence, reducing disease risk and supporting long-term health and resilience.
And the good news? It’s never too late to start as my parents have proven in their 80s!
Want to learn more about the role muscle plays in our health? Watch the brilliant Dr Jonathan Sullivan explain why low muscle mass is such a big driver of ‘sick aging’!
