Sarcopenia is probably not a word you hear thrown around often. I certainly hadn’t heard of it until I began studying exercise science. However, it’s a concept many of us understand intuitively, even if we don’t know it.

The problem within the health services and sciences community is that there isn’t one accepted definition of sarcopenia, or universally acknowledged diagnostic criteria, but that’s gradually changing.

I won’t bore you with the history of the definition of sarcopenia. I’ll just discuss what we currently consider to be sarcopenia and what we know about it thus far.

Sarcopenia is the age-related loss of skeletal muscle mass and function (Coletta & Phillips, 2023). That’s it.

Not too complicated, you may be thinking. We all know from experience that the elderly tend to be weaker, but have you ever stopped to consider why? What about the ageing process causes one to become weaker later in life?

I hate to disappoint you, but while there are many theories and possible mechanisms for this loss in muscle mass and function with age, the principal causal process is currently unknown (Coletta & Phillips, 2023).

Sarcopenia, or age-related muscle loss, is something we might not talk about often, but it affects many of us as we grow older. It can impact mobility, independence, and quality of life, making it an important issue to understand, especially due to our ageing global population.

Let’s take a step back for a second and briefly consider why muscle mass and function are important for healthy ageing.

Muscle mass is required for movement and mobility, to carry out daily activities and maintain independence. A loss in muscle mass due to sarcopenia has also been linked to a reduction in metabolism and fat infiltration into the muscle (McGregor et al., 2014). This can reduce muscle quality, which in turn can further impair movement.

It is known that muscle power begins decreasing around age 30 (Gava et al., 2015) and that muscle mass begins declining around middle age (Wilkinson et al., 2018). Therefore, maintaining muscle mass into old age is no mean feat. However, it is essential for preventing disability in later years.

It is widely accepted that it is more difficult to build muscle in the elderly (McLeod et al., 2016). This then leads to impairment in increasing muscle mass and strength, which has been linked to mortality in elderly populations (McLeod et al., 2016).

So, how can you tell if you’re at risk of developing sarcopenia?

When it comes to sarcopenia, it is well-documented that there are certain factors that put one at increased risk of developing the condition. While some are out of our control, others can be directly targeted.

What are the risk factors for sarcopenia?

• Age (Therakomen et al., 2020). This is unsurprising, considering sarcopenia is the age-related loss of skeletal muscle mass and function. However, it’s worth noting that the European Working Group on Sarcopenia in Older People (EWGSOP) posits that sarcopenia may actually begin earlier in life (Cruz-Jentoft et al., 2019).
  
  
• Biological sex. Males are more likely to develop sarcopenia later in life when compared to females (Therakomen et al., 2020). This may be due to the significant loss in testosterone and insulin-like growth factor-1 (a growth-inducing hormone) that is seen in males with ageing (Sattler et al., 2009).
  
  
• Malnutrition. Sarcopenia may develop as a result of insufficient energy and/or protein intake (Cruz-Jentoft et al., 2019). If we’re breaking down muscle mass faster than we can replace it, this will result in muscle atrophy (breakdown of muscle tissue resulting in a decrease in muscle size, and therefore function).
  
  
• Low levels of physical activity (Landi et al., 2012; Therakomen et al., 2020). There is a high degree of consensus around this. There appears to be a strong association between low levels of physical activity and sarcopenia in older adults, both in the community (Therakomen et al., 2020) and in nursing homes (Landi et al., 2012).
  
  
• Prefrailty (Therakomen et al., 2020). Prefrailty is an intermediate stage between being healthy and frailty being established, and it has been found to be a significant risk factor for sarcopenia (Therakomen et al., 2020). Frailty can be established in the case of weight loss, loss of muscle mass and strength, increased fatigue, reduced tolerance to exercise, reduced walking speed, and a reduced ability for the body to adapt to physiological stressors (a decreased physiological reserve). Prefrailty can be established when some, but not all of these signs are present.

A somewhat hot and highly debated topic in this area is the role of obesity in sarcopenic adults. Due to age-related changes in body composition, namely an increase in body fat and a decrease in muscle mass, we often see sarcopenia coexist with obesity (Wannamethee & Atkins, 2015). This combination of conditions is known as sarcopenic obesity and it may result in higher cardiovascular risk factors and an increased risk of mortality compared to obesity or sarcopenia alone (Wannamethee & Atkins, 2015).

Despite this, some argue that obesity may actually be a protective factor against sarcopenia, as the increase in mechanical load placed on the body due to obesity may help preserve muscle mass better (Santos et al., 2018).

Regardless of any potential positive effects of obesity on sarcopenia, obesity carries its own risks. It is therefore far better to increase lean muscle mass in order to prevent sarcopenia than to rely on obesity to offer a protective effect.

How much of a problem is this, really?

It’s not entirely uncommon. In fact, studies have shown that it may affect around 10% of community-dwelling elderly individuals (Therakomen et al., 2020) and over 30% of nursing home residents (Landi et al., 2012)!

While there is only one main symptom of sarcopenia – feeling weak (Malmstrom et al., 2015) – this may have an impact on many aspects of daily living.

This increased weakness may lead to higher levels of fatigue, issues with balance, an increased risk of falls, and problems with daily tasks like climbing stairs and, in later stages, even walking. These consequences of sarcopenia may have a negative impact on one’s quality of life and independence, potentially altering the individual’s life (generally for the worse).

In the case of falls, this may lead to hospitalisation where even more rapid muscle loss generally ensues (Wan et al., 2023), potentially resulting in a loss of independence. Unfortunately, sarcopenia has also been linked to an increased risk of mortality (Cruz-Jentcroft et al., 2019; Malmstrom et al., 2015).

In addition, sarcopenia has been linked to other age-related conditions, such as osteoporosis/osteopenia (Santos et al., 2018) and may exacerbate the risks associated with other comorbid conditions, such as chronic kidney disease (Wilkinson et al., 2021). In the case of chronic kidney disease, those who also have sarcopenia are at increased risk of end-stage kidney disease and mortality (Wilkinson et al., 2021).

So how can we protect ourselves against it?

There currently do not appear to be any accepted pharmacological treatments for sarcopenia, and in fact, it is much easier to prevent muscle loss than it is to reverse it (Coletta & Phillips, 2023). Coletta and Phillips (2023) suggest beginning lifestyle interventions to combat sarcopenia earlier in life as a preventative mechanism rather than waiting until sarcopenia has already begun to develop. It is far more difficult to undo declines in muscle mass and function than to mitigate this earlier.

While many try, it’s not really possible to stop ourselves from ageing. Equally, we can’t change whether we’re biologically and physiologically male or female. However, there are some lifestyle choices we can make that can help reduce our chances of developing sarcopenia.

Because I’m an exercise physiologist, I don’t discuss nutrition much, but I would be remiss if I did not point out the importance of diet in the context of sarcopenia.

The EWGSOP recommends an optimal protein intake – a sentiment echoed by many studies and other groups (e.g. the ESPEN Expert group [Deutz et al., 2014]). What is the optimal protein intake, you may be wondering?

Adults are normally recommended 0.8 grams of protein for every kilogram of body mass. However, older adults are recommended 1-1.5 grams of protein for every kilogram of body mass (Deutz et al., 2014). McKendry et al. (2020) suggests that older adults could even consume 1.6 grams of protein per kilogram of body mass. That’s double the recommended intake for adults!

They also recommend consuming high-quality protein and suggest that the highest-quality sources of protein are animal-derived, such as from meat, fish, eggs, and dairy.

In combination with resistance exercise, an optimal protein intake from high-quality protein sources can result in greater muscle hypertrophy (increase in muscle size and mass; McKendry et al., 2020).

As I have just alluded to, while there’s yet no magic pill for sarcopenia, we already have one very important and powerful tool we can use to fight back: exercise.

Resistance training is the most potent non-pharmacological skeletal muscle mass and strength builder, and therefore the single best protector against sarcopenia (McKendry et al., 2020). This is because resistance exercise stimulates muscle protein synthesis (which means it builds up the proteins that form muscle), leading to hypertrophy (increase in muscle mass and size), and increases in strength.

Additionally, Terakomen et al. (2020) found that physical activity burning less than 400 kcal a day, such as daily chores around the house or gardening, was not enough to protect against sarcopenia. Therefore, it is important for older adults to spend less time sitting down and to engage in physical activity that burns more than 400 kcal a day.

Sarcopenia has been widely observed in older adults who have a more sedentary lifestyle (Deutz et al., 2014), as physical inactivity has been shown to be a risk factor for developing the condition (Landi et al., 2012). So to combat sarcopenia, we should really be sitting less.

What exercise should you be doing to avoid sarcopenia?

Regular physical activity is important for the prevention of chronic diseases and the mitigation of mobility disability in the elderly (Coletta & Phillips, 2023). Various studies have shown that both resistance exercise and aerobic training are effective for maintaining mobility in older adults, with resistance training recommended as the optimal form of exercise to prevent age-related muscle atrophy (Coletta & Phillips, 2023).

Hurst et al. (2022) recommend adhering to a resistance training programme consisting of at least two weekly exercise sessions, combining both upper and lower body exercises. They recommend performing these exercises to a high degree of effort for 1-3 sets of 6-12 repetitions each to effectively treat sarcopenia.

Depending on preference, they specify that resistance can be employed using resistance machines, free weights, resistance bands, or even simply using one’s own bodyweight.

So, if you’re new to resistance training, start small. Even bodyweight exercises like squats, lunges, and push-ups can help. Aim for two days of resistance training a week and gradually increase exercise intensity as your strength improves.

If you’re in the UK and don’t know where to start, Age UK offers a variety of exercise classes for seniors, which can be a great way to get active in a fun and social environment.

In the USA, SilverSneakers is a good option. They offer both online classes and in-person sessions at various locations around the country. So, pop on a pair of trainers and join a fitness class – you’ll learn plenty about what kind of exercise you should be doing.

Summary and Concluding Thoughts

Sarcopenia, or muscle failure, is a disease that results in adverse muscle changes accumulating over one’s lifetime (Cruz-Jentcroft et al., 2019). Sarcopenia is present when one exhibits low muscle strength, low muscle quantity and quality, and low physical performance (Cruz-Jentcroft et al., 2019). While it is common in the elderly, it can also occur earlier in life (Cruz-Jentcroft et al., 2019).

In order to prevent sarcopenia from developing, older adults should consume at least 1 gram of protein per kilogram of body mass, with 1.5-1.6 grams per kilogram of body mass being ideal, particularly for those who are malnourished and/or suffering from acute or chronic illness (Deutz et al., 2014). An even higher intake is recommended for those with severe illness or injury.

The most important step one can take to reduce the risk of developing sarcopenia is daily physical activity and exercise. It is important to avoid a sedentary lifestyle and incorporate weekly resistance training sessions, although even aerobic exercise can be highly beneficial (Deutz et al., 2014). For as long as one is physically able, training should be sustained well into old age (Deutz et al., 2014).

Now that you understand more about sarcopenia, it’s time to take action. Whether it’s a brisk walk, a resistance training session, or improving your diet, every little bit counts. As always, keep trying to move more and sit less. Start small, and remember: even in your later years, it’s never too late to build up muscle and protect your health.

P.S. Please don’t forget to consult your GP before starting or changing your exercise programme!

References

Age UK. (2019). Exercise and keep fit classes for seniors. Age UK. https://www.ageuk.org.uk/services/in-your-area/exercise/

Coletta, G., & Phillips, S. M. (2023). An elusive consensus definition of sarcopenia impedes research and clinical treatment: A narrative review. Ageing Research Reviews, 86, 101883. https://doi.org/10.1016/j.arr.2023.101883

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