Sarcopenia: Muscle Loss That Starts in Your 40s

Most people assume that the weakness, weight loss and reduced energy they notice in older relatives are just “getting old”. In many cases, there is a specific, named process at work: sarcopenia. It is the progressive loss of muscle mass and strength that accompanies ageing, and it carries consequences that go well beyond feeling a bit tired.

The good news is that sarcopenia is not inevitable. With the right type of exercise, introduced at the right time, muscle loss is largely preventable and, in many cases, reversible.

When does muscle loss begin?

Muscle mass starts to decline gradually from around age 30. The pace picks up from the mid-40s onwards, and after 60 the losses become more significant. Research suggests that adults can lose 3 to 8 percent of their muscle mass per decade in middle age, with that rate accelerating after 70.

For most people, this goes unnoticed for years. There are no obvious symptoms in the early stages. You might notice that carrying shopping is a little harder, that you tire more quickly on the stairs, or that you feel less steady on your feet. By the time these things become noticeable, meaningful muscle has already been lost.

A 2023 systematic review found the weighted prevalence of sarcopenia in African populations to be around 26%, with rates varying depending on the diagnostic criteria used. The condition is under-recognised in South Africa, where older adults are often not assessed until they present with a fall or fracture.

Why does it matter?

Muscle does far more than move limbs. It is metabolically active tissue that plays a role in blood sugar regulation, immune function and bone health. Significant muscle loss has the following consequences:

Increased fall risk. Reduced lower limb strength compromises balance and reaction time.
Greater fracture risk. Muscle protects bone indirectly by absorbing force and reducing the impact of falls.
Reduced independence. Everyday tasks like getting up from a chair, climbing stairs and carrying objects become difficult.
Poorer recovery from illness or surgery. People with sarcopenia take longer to recover from hospital admissions and have higher complication rates.
Metabolic effects. Less muscle means reduced resting metabolic rate, which contributes to weight gain and can worsen insulin resistance.

Sarcopenia also has a psychological dimension. Losing the physical capacity to do things you have always done affects confidence, mood and independence. Many older adults begin to limit their activities out of caution, which accelerates the decline further.

What causes sarcopenia?

The mechanisms are complex and involve several overlapping processes: reduced production of anabolic hormones (particularly testosterone and growth hormone), decreased protein synthesis in muscle tissue, chronic low-grade inflammation, and reduced nerve signalling to muscle fibres. Physical inactivity accelerates all these processes, while regular exercise counteracts them.

Nutrition plays a role too. Inadequate protein intake is common in older adults and compounds the problem. Most guidelines recommend at least 1.2 grams of protein per kilogram of body weight per day for older adults, which is higher than the general population target.

Why resistance training is the answer

Of all the interventions studied, resistance training has the most consistent and robust evidence base. A 2022 meta-analysis found that structured resistance exercise programmes significantly improved grip strength, gait speed and skeletal muscle index in older adults with sarcopenia. The international clinical guidelines from the ICFSR (International Conference on Frailty and Sarcopenia Research) recommend resistance training as the primary intervention.

Resistance training works by stimulating muscle protein synthesis, improving neuromuscular coordination, and triggering adaptations in both muscle fibres and the nervous system. It does not require heavy weights or gym membership. Progressive resistance using bands, body weight, or light dumbbells is effective, provided it is progressive, meaning you gradually increase the challenge over time.

Two to three sessions per week, targeting all major muscle groups, is the standard recommendation. Exercises such as squats, step-ups, seated leg presses, rows, and shoulder presses all have direct functional applications for older adults.

How a biokineticist helps

A biokineticist is a registered clinical exercise specialist trained to assess muscle strength, function and movement, then design a programme that matches your current capacity and progresses safely over time. This is important because older adults with sarcopenia are often also managing other conditions, such as osteoporosis, arthritis, cardiovascular disease or diabetes, and the exercise prescription needs to account for all of these.

At JW Bio, we conduct a full initial assessment before writing any programme. We look at strength, balance, gait and functional movement, so that the work you do in sessions addresses what needs attention, rather than following a generic template.

The goal is straightforward: maintain or rebuild muscle, reduce your fall risk, and keep you doing the things that matter to you for as long as possible.

Need a hand?

If you are concerned about muscle loss, balance or general strength, we are happy to do an assessment and talk through the options. Visit our exercise for older adults page or get in touch to book a session.