Muscle loss in older age: what sarcopenia is, how fast it happens and what to do

What is sarcopenia, and how is it different from normal ageing?

Sarcopenia is the name for a muscle disorder that goes beyond what everyone experiences as they get older. The European Working Group on Sarcopenia in Older People, whose 2019 consensus (EWGSOP2) includes authors from Southampton and Newcastle, defines it as a progressive and generalised disorder of the skeletal muscles. It is associated with a higher likelihood of falls, fractures, physical disability and death.¹

The same consensus describes a disease of the muscle that builds up from unfavourable changes across a lifetime. It is common in later life but can also occur earlier.² So the line between “normal ageing” and sarcopenia is not an age. It is a matter of how weak or slow a person has become, judged by a clinician.

One idea in that consensus is easy to miss and useful for readers. It puts strength first. Low muscle strength is the main criterion and points to probable sarcopenia. Low muscle quantity or quality confirms it. Low physical performance, such as slow walking, marks a severe case.¹ The consensus gives its reason in short form: strength predicts bad outcomes better than mass does.¹

That is why this guide spends more time on strength and everyday function than on a number of kilograms. For the separate question of what “muscle mass” means as a measurement, and how it differs from lean mass, see muscle mass explained.

How fast does muscle shrink after 50?

The consensus describes a rise and a fall. Muscle mass and strength reach their peak up to about the age of 40, and the peak is higher in men. Beyond 50, a loss of leg muscle mass of 1 to 2 per cent a year and a loss of strength of 1.5 to 5 per cent a year have been reported.¹ The consensus gives these figures with a reference to an earlier study, which was not read for this guide, so treat them as reported ranges and not as a prediction for any one person.

Two cautions come with those numbers. First, the 1 to 2 per cent is for leg muscle, not for the whole body and not for body weight. Second, nothing in the sources read says that the loss starts on a 50th birthday. The consensus places the peak up to about 40 and speaks of maintaining muscle in middle age.¹ Grip strength in 12 British studies peaks in early adult life, between about 26 and 42, and then declines “from midlife onwards”.¹⁰ The UK Chief Medical Officers write that the natural decline occurs from around 50.⁸

Seeing the size of 1 per cent a year

A percentage a year sounds small. Over a decade, it compounds. The example below is arithmetic on an assumption, not a forecast and not a measurement. The 1 per cent is chosen from the lower end of the reported range for leg muscle, and the starting weight is invented.

The point of the example is scale. A slow, steady loss in a muscle group can add up to something noticeable over ten years, and it can be slowed. It is also easy to overstate. No source read for this guide supports a “per cent lost by 80” headline, so none is given.

Who is more likely to lose muscle, and why?

The consensus separates two kinds. Sarcopenia is called primary, or age-related, when no other specific cause is evident. It is called secondary when something else contributes.¹

• Illness. Systemic disease such as cancer or organ failure is listed as a secondary cause.¹
• Inactivity. A sedentary lifestyle, or immobility caused by an illness, also contributes.¹
• Too little energy or protein in the diet. The consensus lists insufficient intake of energy or protein as a secondary cause.¹

Where the lines blur, the practical message is the same. Staying active, and not letting an illness or a long spell of rest take away strength, matters. The NHS notes that strength activities slow the rate of bone and muscle loss associated with ageing and may reduce the risk of falls.⁴

On food, this guide gives no protein target. No British source read for this page states how much protein adults over 50 need, so a figure would be a guess. The NHS Eatwell Guide lists beans, fish, eggs and meat among protein foods but, in the version read, gives no amount for older people. Its page shows a review date that has passed.¹³ If you are unsure what to eat, or you are losing weight without trying, speak to a GP.

How common is it in the UK?

There is no national UK rate in the sources read. What exists are studies of particular groups, and their results depend on how sarcopenia was defined.

In the Hertfordshire Cohort Study, the prevalence of sarcopenia, using an earlier European definition, was 4.6 per cent in men and 7.9 per cent in women, with an average age of 67 (765 men and 1,022 women). The cut-off was the lowest third of fat-free mass in that cohort, so the result describes that group and does not mean “1 in X British people”.⁹ In 103 men of the Hertfordshire Sarcopenia Study, average age 73, it was 6.8 per cent by DXA lean mass and 7.8 per cent by skinfold-based fat-free mass.⁹

British grip-strength data (12 studies, 49,964 people) show weak grip rising sharply with age, reaching 23 per cent of men and 27 per cent of women by 80; the full figures, including the age at which grip peaks, are in the muscle mass explained guide.¹⁰

What can you check at home, and what can you not?

Some tests used in clinics can be tried in a rough form at home, with limits. The table sets out what each one is, the published threshold and why a home result is not a diagnosis. All thresholds come from the European consensus, which was written for clinicians and researchers.¹

The consensus calls walking speed a quick, safe and highly reliable test for sarcopenia, one that predicts disability, falls and death.¹ A negative SARC-F is the one to be careful with, because the questionnaire is better at ruling in severe cases than at ruling out milder ones.¹

A rough chair-stand check

1. Check you are fit to try it. The NHS says to talk to a GP first if you have not exercised for a while or have a medical condition.³
2. Use the NHS movement. Sit on a chair, then stand up slowly using your legs, not your arms.⁵
3. Repeat five times and time it. The consensus test times five rises from a seated position without the arms.¹
4. Compare with the threshold. More than 15 seconds for five rises is the consensus cut-off for low strength.¹ Treat it as a prompt to talk to a GP, not as a result.
5. Repeat the same way later. Use the same chair and method so that a change means something.

What can a smart scale tell you about muscle?

A body composition scale gives a muscle figure, but it is an estimate. The consensus states that bioimpedance equipment does not measure muscle mass directly.¹ Instead it works out a value from how easily a small electrical current passes through the body, using an equation calibrated against DXA.¹ For the full comparison, see DEXA scan versus smart scale and how accurate smart scales are.

So a scale can help you notice a direction over weeks. It cannot tell you that muscle loss has become a medical problem. If your strength, your walking or your confidence on stairs is changing, that is the thing to raise with a GP, whatever the scale shows.

What helps: strength training and staying active

The consensus says nutrition and exercise training seem to slow or reverse these processes. The aim is to build as much muscle as possible when young, keep it in middle age and limit loss later.¹ “Seem to” is the careful wording to keep in mind. Nobody can promise to bring back lost muscle.

The strongest evidence read here is for strength training. A Cochrane review of 121 trials with about 6,700 older participants found a large positive effect of progressive resistance training on muscle strength (73 trials, standardised mean difference 0.84). It also found better walking speed, by about 0.08 m/s, and better chair-rise performance. Serious adverse events were rare, but they were poorly recorded, so the authors urge caution for clinical groups.¹¹ The review dates from 2009.

What the NHS and the UK Chief Medical Officers say

• Adults aged 65 and over: activities to improve strength, balance and flexibility on at least 2 days a week.³
• Strength exercises: aim for 8 to 12 repetitions of each activity, at least 2 sets, with 3 for more benefit, building up gradually.⁴
• The NHS home exercises: do them at least twice a week and add repetitions gradually.⁵
• UK Chief Medical Officers: strength and balance programmes based on evidence reduce the rate and risk of falls. They also describe loss of muscle strength in later life as the main limit on independence.⁸

For routines you can do without a gym, see strength training at home and the strength training guidelines. For how weak muscles fit into the wider risk of falling, see falls prevention for older adults and how falls risk is assessed. The NHS lists muscles getting weaker with age among the causes of falls.⁶ A programme built for older adults is set out in strength training for seniors, and if you are also thinking about energy needs, see how to calculate BMR.

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