Dr Kathryn Fox is an Australian medical doctor and bestselling crime writer, best known for her forensic thrillers featuring pathologist Dr Anya Crichton. Drawing on her medical expertise, she crafts gripping, authentic crime fiction and is also a passionate advocate for forensic medicine education and public engagement. Her columns appear every Monday and Thursday.
When we think of healthy ageing, the focus is often on heart health, brain health, or staying active. There’s one multitasking body system that quietly influences all of these – and it’s often talked about but underestimated: muscle.
Skeletal muscle – the type attached to bones – accounts for about 30–40 percent of our body weight and plays several vital roles beyond strength and balance. It helps to maintain posture, stabilise joints, regulate temperature and even manage metabolism. The more muscle, the faster the metabolism. Because muscle generates heat, age-related muscle loss can also cause increased sensitivity to cold.
And importantly, muscle acts like an endocrine organ – meaning it releases chemical messengers called myokines that communicate with other parts of the body. They’re released when muscles contract during movement or exercise and act both locally within muscles and beyond, travelling through the bloodstream to influence organs such as the brain, liver, fat tissue, pancreas and even the heart.
This muscle-to-organ communication helps explain why strong muscles are linked with better overall health, independent of other lifestyle factors.
A recent overview from the Institute for Functional Medicine highlights research suggesting that higher skeletal muscle mass is associated with lower cardiovascular risk. More skeletal muscle and greater muscle strength are strongly associated with lower risk of cardiovascular disease. long-term study of middle-aged and older adults without pre-existing heart disease found that those with the most muscle mass had an 81% lower risk of developing cardiovascular disease over ten years compared with those with the least muscle.
Another recent study found that relative muscle strength – especially grip strength – was linked to lower rates of heart disease.
These associations don’t prove causation, but they show that muscle health often goes hand-in-hand with heart health. A heart is, after all, cardiac muscle that functions all day, every day of our lives.
Muscle is a major regulator of metabolism. It plays a key role in how the body handles glucose (sugar), which helps support healthy blood sugar levels and reduces the risk of type 2 diabetes. Exercise triggers the release of myokines that help reduce inflammation and improve insulin sensitivity, mechanisms that researchers believe are part of how physical activity protects against chronic diseases.
Muscle doesn’t just support movement – it supports metabolic balance.
As we age, muscle mass and strength naturally decline in a process called sarcopenia. That decline can begin as early as age 30 and accelerates in later decades.
Sarcopenia isn’t harmless. Loss of muscle strength and size is linked with:
Higher risk of falls and fractures
Reduced ability to perform everyday tasks
Greater frailty and loss of independence
Higher risk of chronic disease and mortality
In other words, maintaining muscle isn’t just about lifting heavy things – it’s essential for resilience, independence and quality of life as we age.
The good news is that muscles can still get stronger, even later in life. Age doesn’t stop muscles adapting – it just changes how we need to work with our bodies.
Here are evidence-based strategies to support muscle health:
1. Prioritise Resistance Training
Strength or resistance training – using hand weights, resistance bands, or bodyweight – signals muscles to grow and adapt. This type of exercise is among the strongest predictors of preserved muscle strength and mass in older adults.
Aim for 2–3 resistance sessions per week targeting all the major muscle groups.
2. Consume adequate protein.
Muscle building requires protein. As we age, our bodies become less efficient at using protein to build muscle (“anabolic resistance”), so higher protein intake and spreading it throughout the day helps stimulate muscle synthesis. Check with your doctor if you have kidney problems.
Focus on lean meats, fish, legumes, dairy, eggs or other high-quality sources.
3. Stay Active Overall
Sedentary behaviour accelerates muscle loss and metabolic decline. Even simple daily movement – walking, gardening, housework – helps maintain muscle engagement and supports overall health.
4. Combine with Aerobic Activity
Aerobic exercise like brisk walking, swimming or cycling enhances cardiovascular fitness. When combined with strength work, it supports both heart and muscle health.
Science increasingly shows that preserving muscle into older adulthood is a cornerstone of healthy ageing — not a bonus.
Muscle isn’t just about strength. It’s a signalling organ that communicates with heart, metabolism, immune function and even the brain.
Stronger muscles help us stay independent, mobile, steady on our feet, and resilient in the face of illness and surgery. Keeping muscles strong is about quality of life: living better, not just longer.