What is Sarcopenia

  • Sean AspinallDoctor of Philosophy (PhD), Cystic Fibrosis, Swansea University

Overview

Sarcopenia is classically defined as the ‘age related-decline in skeletal muscle mass (SMM) and function’.1 Whilst sarcopenia is primarily a disease of the elderly, its development can also be associated with certain medical conditions, such as disuse, malnutrition, and cachexia.2

Some level of muscle mass loss is considered normal. After individuals reach 30 years old, they can lose 3-5% of their muscle strength each year on average.3 However, sarcopenia describes a loss of muscle mass that exceeds the norm.

Whilst the etiology of sarcopenia is not yet fully understood, treatments and interventions surrounding exercise and nutrition are being explored as potential treatments to combat this age-related loss of muscle mass.

Symptoms

This progressive and generalised loss in skeletal muscle mass and strength is strongly correlated with a physical disability, poor quality of life, and loss of autonomy that can often result in the need for long-term care.2

Common symptoms of sarcopenia include

  • Loss of stamina
  • Low skeletal muscle mass
  • Loss in weight
  • Walking slowly
  • Poor balance due to increased number of falls
  • Difficulty performing day-to-day activity

Further to this, sarcopenia may also result in increased rates of hospitalisation, increase duration of stays in the hospital as well as being considered an important risk factor for increased mortality as an individual age.4

Diagnosis

Whilst there is not a single test best to identify sarcopenia, it’s likely that if your healthcare provider thinks you may be at risk you may undergo a selection of tests to determine whether you do have sarcopenia, and to what severity.

Screening

A simple questionnaire based on self-reported symptoms. These questions will explore factors such as muscle strength, need for assistance in walking, difficulty getting up from a chair, difficulty climbing stairs, and falls within the last year. Each factor is scored from 0-2, with an overall score of >4 representing a limitation in physical activity and a high probability for adverse outcomes.

Testing muscle strength

In clinical practice it is common to complete a handgrip strength (HGS) test to identify sarcopenia. HGS testing draws parallel with strength in other muscles in your body and is associated with low limb strength and disability.5

Values below 27kg for men and 16kg for women may imply strength deficiency related to sarcopenia.5

Alternatively, a chair stand test is used. The test measures the number of times you can stand and sit from the chair within 30 seconds without using your arms. Results show that for every 1s increase in test performance, the likelihood of sarcopenia increases by 8%.6

Measures of physical performance

The short physical performance battery (SPPB) and gait speed are considered the most reliable performance tests when looking for sarcopenia. The SPPB evaluates muscle strength and endurance by performing 3 tasks: chair stand test, standing balance test, and walking speed test.

Where this can’t be performed the time up and go test will be used. You will be measured on your capability to get up from a chair, walk ten feet, turn around, and return to the chair. A time of over 20 seconds is considered a sign of poor physical performance.7

Imagining and body composition

Analysis of body composition and muscle mass directly will help further inform a sarcopenia diagnosis. Dual-energy X-ray absorptiometry (DXA) and bioelectrical impedance analysis (BIA) will show the amount of fat mass, lean mass, and bone density to identify low levels of muscle mass or track muscle loss over time.

Causes of sarcopenia

Whilst the cause of sarcopenia can be largely attributed to the ageing process, in many cases this is not the only contributing factor to a loss in muscle mass.

Indeed, researchers believe the cause to be multifactorial with other potential causes including:

  • Physical inactivity
  • Obesity
  • Chronic disease
  • High levels of inflammation
  • Reduced calorie and protein intake
  • Reduction in hormone levels
  • Decreased activity in the nerve cells in the spinal cord telling your brain to move your muscles

Treatment for sarcopenia

Currently, there are no ‘accepted’ pharmaceutical treatments for sarcopenia.8 Much of the research suggests that preventing a decline in muscle mass is easier than an intervention aimed at gaining muscle mass and, as such, lifestyle interventions are considered the current best option to manage sarcopenia.

Exercise to fight sarcopenia

People who maintain a sedentary lifestyle pose the risk of greater and faster muscle mass loss. The best way to combat sarcopenia is through physical activity and exercise.9 Regular exercise is considered the foundation for combating chronic disease and decreasing the likelihood of mobility issues in older adults.10-11

Current UK guidelines suggest that adults over the age of 65 years should be:

  • Aiming to be physically active daily, even if light
  • Exercise focusing on strength, balance, and mobility 2 days per week
  • At least 150 minutes of moderate-intensity activity or 75 minutes of vigorous activity per week
  • Reduce time sitting and lying down where possible

The key component to preventing sarcopenia, however, is focused on resistance training or weight training. As you apply mechanical tension to the muscle, you cause stress and damage to the muscle which then repairs larger and stronger than before.12

Collectively, applying this over a prolonged period will help create a positive environment for muscular adaptation and the retention of muscle mass. As such, resistance training is considered to be the best method for the treatment of age-related muscle loss, by improving muscle strength, mass, and function in older adults.13-14

What is important to note is that resistance training doesn’t have to be all heavyweights Resistance can be a mixture of machines, free weights, bodyweight exercises or resistance bands.

A resistance training programme consisting of a combination of upper- and lower-body exercises, performed with a relatively high degree of effort for 1-3 sets of 6-12 reps is an effective treatment for sarcopenia.15

However, there is consensus that resistance training is an imperative intervention for treating sarcopenia.15-16

Preventing sarcopenia through your diet

Calories

Deficiencies in both calories and protein have been identified as considerable contributing factors to the development of sarcopenia as an individual ages.

First off, it is key to have some understanding of your required individual calorie intake:

Ensuring that you at least meet your daily calorie needs is essential to ensure that your body is in a positive place to retain all your muscle mass.

Protein

Protein is an essential nutrient needed for your body to create muscle mass. Consuming protein provides your body with the necessary amino acids which function as the ‘building blocks’ of your muscle and help reduce the likelihood of muscle breakdown.17

The current recommended daily allowance (RDA) for protein is 0.8 grams per kilogram of body weight (g/kg), regardless of age.18

However, as the body ages, it undergoes processes which means the utilisation of this protein is altered and potentially reduced. As such, it is likely that as an older individual, you would need to exceed the current RDA to gain a beneficial effect on muscle mass. Research has shown that older adults (70-79) who exceeded the RDA lost 40% less lean body mass over 3 years, versus those who consumed the RDA.19

Considering all the factors included in the age-related decline in lean mass, it is recommended that20-21

  • Healthy individuals over 65 years consume 1.0-1.2g/kg of protein daily
  • Individuals over the age of 65 years with chronic illness should consume 1.2-1.5g/kg protein daily

However, it is worth noting, prevention of sarcopenia is considered the best course of action. Considering that is it estimated individuals will lose 0.5-1% of muscle mass annually from the age of 50 years.19 It is suggested that increased protein intake should occur earlier in life to further reduce any risks of muscle ageing.

A list of where to find good quality protein sources is here.

SummarySarcopenia is a common condition in older adults, contributing to decreased muscle mass and strength which leads to functional decline, disability, frailty, and falls.

The cause of sarcopenia is considered multifactorial with declines in activity, poor nutritional status, disease, inflammation, and age-related changes in protein metabolism and hormone function, all suggested to play critical roles in its development.

Whilst there are no current pharmacological interventions deemed effective for the treatment of sarcopenia, many clinical interventions focus on the role that exercise and nutrition have to play in the preservation of muscle mass with age.

The consensus is that eating enough calories, having a higher protein intake, and partaking in resistance exercise, whilst maintaining a good level of physical activity, might be enough to fight sarcopenia even into old age.

FAQ’s

I don’t eat meat; how do I get enough protein?

In most cases plant-based foods may be incomplete in their amino acid profile, meaning that alone, they may not contribute fully to retention of muscle mass. Similarly, compared to animal-based protein, plant proteins may be relatively low in the compound leucine (needed to stimulate muscle building).

However, when combined properly in a meal, plant-based foods can meet the demands needed to stimulate muscle growth. A list of the top 10 vegan proteins can be found here.

It is not uncommon to struggle with hitting your protein target if you are not consuming animal products. If you do struggle, then consuming a high-quality protein supplement will help make the job a little easier.

Are there any supplements that I can take to help me?

Yes, although it is worth noting that any supplement should be in supplement of positive dietary changes, including these alone will not affect your management of sarcopenia.

There is some research suggesting that Vitamin D may help increase muscle strength and reduce falls in those with sarcopenia, however, the best dose is still yet to be reported.22

Omega-3 is beneficial in lowering inflammation levels and may also be responsible in part for aiding in muscle growth. It has been found that around 2g per day [combined with resistance exercise] can increase muscle strength.23

References

  1. Walston, Jeremy D. ‘Sarcopenia in Older Adults’. Current Opinion in Rheumatology, vol. 24, no. 6, Nov. 2012, pp. 623–27. PubMed Central, https://doi.org/10.1097/BOR.0b013e328358d59b.
  2. Santilli, Valter, et al. ‘Clinical Definition of Sarcopenia’. Clinical Cases in Mineral and Bone Metabolism, vol. 11, no. 3, 2014, pp. 177–80. PubMed Central, https://www.ncbi.nlm.nih.gov/pmc/articles/PMC4269139/.
  3. Volpi, Elena, et al. ‘Muscle Tissue Changes with Aging’. Current Opinion in Clinical Nutrition and Metabolic Care, vol. 7, no. 4, July 2004, pp. 405–10. PubMed Central, https://www.ncbi.nlm.nih.gov/pmc/articles/PMC2804956/.
  4. Filippin, Lidiane Isabel, et al. ‘Sarcopenia: A Predictor of Mortality and the Need for Early Diagnosis and Intervention’. Aging Clinical and Experimental Research, vol. 27, no. 3, June 2015, pp. 249–54. PubMed, https://doi.org/10.1007/s40520-014-0281-4.
  5. Beaudart, Charlotte, et al. ‘Sarcopenia in Daily Practice: Assessment and Management’. BMC Geriatrics, vol. 16, no. 1, Oct. 2016, p. 170. BioMed Central, https://doi.org/10.1186/s12877-016-0349
  6. Cruz-Jentoft, Alfonso J., et al. ‘Sarcopenia: Revised European Consensus on Definition and Diagnosis’. Age and Ageing, vol. 48, no. 1, Jan. 2019, pp. 16–31. PubMed Central, https://doi.org/10.1093/ageing/afy169.
  7. Giovannini, Silvia, et al. ‘Sarcopenia: Diagnosis and Management, State of the Art and Contribution of Ultrasound’. Journal of Clinical Medicine, vol. 10, no. 23, Nov. 2021, p. 5552. PubMed Central, https://doi.org/10.3390/jcm10235552.
  8. Rooks, Daniel, et al. ‘Bimagrumab vs Optimized Standard of Care for Treatment of Sarcopenia in Community-Dwelling Older Adults: A Randomized Clinical Trial’. JAMA Network Open, vol. 3, no. 10, Oct. 2020, p. e2020836. Silverchair, https://doi.org/10.1001/jamanetworkopen.2020.20836.
  9. Coletta, Giulia, and Stuart M. Phillips. ‘An Elusive Consensus Definition of Sarcopenia Impedes Research and Clinical Treatment: A Narrative Review’. Ageing Research Reviews, vol. 86, Apr. 2023, p. 101883. ScienceDirect, https://doi.org/10.1016/j.arr.2023.101883.
  10. Bull, Fiona C., et al. ‘World Health Organization 2020 Guidelines on Physical Activity and Sedentary Behaviour’. British Journal of Sports Medicine, vol. 54, no. 24, Dec. 2020, pp. 1451–62. bjsm.bmj.com, https://doi.org/10.1136/bjsports-2020-102955.
  11. Angulo, Javier, et al. ‘Physical Activity and Exercise: Strategies to Manage Frailty’. Redox Biology, vol. 35, Aug. 2020, p. 101513. ScienceDirect, https://doi.org/10.1016/j.redox.2020.101513.
  12. Schoenfeld, Brad J. ‘The Mechanisms of Muscle Hypertrophy and Their Application to Resistance Training’. The Journal of Strength & Conditioning Research, vol. 24, no. 10, Oct. 2010, p. 2857. journals.lww.com, https://doi.org/10.1519/JSC.0b013e3181e840f3.
  13. Grgic, Jozo, et al. ‘Effects of Resistance Training on Muscle Size and Strength in Very Elderly Adults: A Systematic Review and Meta-Analysis of Randomized Controlled Trials’. Sports Medicine, vol. 50, no. 11, Nov. 2020, pp. 1983–99. Springer Link, https://doi.org/10.1007/s40279-020-01331-7.
  14. Straight, Chad R., et al. ‘Effects of Resistance Training on Lower-Extremity Muscle Power in Middle-Aged and Older Adults: A Systematic Review and Meta-Analysis of Randomized Controlled Trials’. Sports Medicine, vol. 46, no. 3, Mar. 2016, pp. 353–64. Springer Link, https://doi.org/10.1007/s40279-015-0418-4.
  15. Hurst, Christopher, et al. ‘Resistance Exercise as a Treatment for Sarcopenia: Prescription and Delivery’. Age and Ageing, vol. 51, no. 2, Feb. 2022, p. afac003. PubMed, https://doi.org/10.1093/ageing/afac003.
  16. Shen, Yanjiao, et al. ‘Effects of Exercise on Patients Important Outcomes in Older People With Sarcopenia: An Umbrella Review of Meta-Analyses of Randomized Controlled Trials’. Frontiers in Medicine, vol. 9, 2022. Frontiers, https://www.frontiersin.org/articles/10.3389/fmed.2022.811746.
  17. Nunes, Everson A., et al. ‘Systematic Review and Meta‐analysis of Protein Intake to Support Muscle Mass and Function in Healthy Adults’. Journal of Cachexia, Sarcopenia and Muscle, vol. 13, no. 2, Apr. 2022, pp. 795–810. DOI.org (Crossref), https://doi.org/10.1002/jcsm.12922.
  18. Trumbo, Paula, et al. ‘Dietary Reference Intakes for Energy, Carbohydrate, Fiber, Fat, Fatty Acids, Cholesterol, Protein and Amino Acids. (Commentary).’ Journal of the American Dietetic Association, vol. 102, no. 11, Nov. 2002, pp. 1621–31. go.gale.com, https://go.gale.com/ps/i.do?p=AONE&sw=w&issn=00028223&v=2.1&it=r&id=GALE%7CA94870700&sid=googleScholar&linkaccess=abs.
  19. Abellan van Kan, G. ‘Epidemiology and Consequences of Sarcopenia’. The Journal of Nutrition, Health & Aging, vol. 13, no. 8, Oct. 2009, pp. 708–12. PubMed, https://doi.org/10.1007/s12603-009-0201-z.
  20. Bauer, Jürgen, et al. ‘Evidence-Based Recommendations for Optimal Dietary Protein Intake in Older People: A Position Paper from the PROT-AGE Study Group’. Journal of the American Medical Directors Association, vol. 14, no. 8, Aug. 2013, pp. 542–59. PubMed, https://doi.org/10.1016/j.jamda.2013.05.021.
  21. Deutz, Nicolaas E. P., et al. ‘Protein Intake and Exercise for Optimal Muscle Function with Aging: Recommendations from the ESPEN Expert Group’. Clinical Nutrition (Edinburgh, Scotland), vol. 33, no. 6, Dec. 2014, pp. 929–36. PubMed, https://doi.org/10.1016/j.clnu.2014.04.007.
  22. Anagnostis, Panagiotis, et al. ‘Sarcopenia in Post-Menopausal Women: Is There Any Role for Vitamin D?’ Maturitas, vol. 82, no. 1, Sept. 2015, pp. 56–64. PubMed, https://doi.org/10.1016/j.maturitas.2015.03.014.
  23. Rodacki, Cintia L. N., et al. ‘Fish-Oil Supplementation Enhances the Effects of Strength Training in Elderly Women’. The American Journal of Clinical Nutrition, vol. 95, no. 2, Feb. 2012, pp. 428–36. PubMed, https://doi.org/10.3945/ajcn.111.021915.
This content is purely informational and isn’t medical guidance. It shouldn’t replace professional medical counsel. Always consult your physician regarding treatment risks and benefits. See our editorial standards for more details.

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