What is sarcopenia?
Sarcopenia is a progressive and generalized skeletal muscle disorder characterized by a loss of muscle mass and strength and is associated with an increased risk of adverse outcomes, including falls, bone fractures, postoperative complications, physical disability, and mortality.[1][2]
There are two types of sarcopenia — primary and secondary. Sarcopenia is considered primary when it results from no other underlying cause except for age.[1] It is considered secondary when causal factors other than age are present, such as disease (e.g., cancer, advanced organ failure), malnutrition, or physical inactivity.
What are the main signs and symptoms of sarcopenia?
- History of recurrent falls
- Feeling weak
- Slow walking speed
- Difficulty rising from a chair
- Recent unintentional weight loss (> 5%)
How is sarcopenia diagnosed?
Muscle mass, strength, and physical performance are assessed to diagnose sarcopenia.[1] Diagnosis starts with muscle strength, usually grip strength measured using a calibrated handheld dynamometer, but lower body strength may also be assessed using the chair stand test, which measures the amount of time it takes the individual to rise five times from a seated position without using their arms. If low muscle strength is determined, muscle quantity is assessed to confirm the presence of sarcopenia. Lastly, physical performance is assessed using scores on the gait speed test, the Short Physical Performance Battery, the Timed-Up and Go test, or the 400-meter walk test to determine the severity of sarcopenia.
What are some of the main medical treatments for sarcopenia?
No specific drugs have been approved for the treatment of sarcopenia. Testosterone treatment may increase muscle mass and strength in older men with low serum testosterone levels (<200–300 ng/mL) and muscle weakness.[3] In addition, preliminary evidence suggests that myostatin inhibitors, which block the actions of myostatin — a protein secreted by muscle cells that inhibits protein synthesis and hypertrophy — may increase muscle mass and some measures of physical performance.[4][5] However, the medical use of myostatin inhibitors as a treatment of sarcopenia is currently limited to clinical trials.
Have any supplements been studied for sarcopenia?
The following supplements have been studied for the treatment of sarcopenia and have shown some efficacy in different scenarios (e.g., when combined with resistance exercise, in people with inadequate dietary intake):[6]
- Protein
- Leucine
- Creatine
- Beta-hydroxy beta-methylbutyrate
- Omega-3 polyunsaturated fatty acids
- Vitamin D
How could diet affect sarcopenia?
Protein is crucial for skeletal muscle growth and maintenance, and older adults display an impaired muscle protein synthesis response to the ingestion of protein,[7] so a large portion of the evidence base revolves around optimizing protein intake for the prevention and treatment of sarcopenia.
Total protein intake should ideally be 1.2–1.6 grams per kilogram of body weight per day, evenly distributed between 3–4 meals containing ≥ 0.4 grams of protein per kilogram of body weight.[6]
With respect to dietary patterns, largely consistent evidence from observational studies demonstrates that higher adherence to a Mediterranean diet is associated with better physical functioning, including lower extremity functioning, mobility, and walking speed.[8][9]
Are there any other treatments for sarcopenia?
Resistance exercise is the most potent non-medical treatment for combatting skeletal muscle deterioration and improving health-related quality of life.[10] It’s traditionally recommended that people perform 2–3 resistance training sessions per week using relatively heavy loads (i.e., 80% of 1-repetition maximum), but more recent evidence suggests that low-load resistance training (i.e., 35–50% of 1-repetition maximum) is similarly effective for increasing muscle mass and strength when performed to volitional fatigue.[6] A combined resistance training and high-protein diet intervention seems to be more effective than either intervention alone.[11]
What causes sarcopenia?
In the case of primary sarcopenia, there is a wide range of factors that contribute to the development of the condition, which are not entirely understood and largely thought to be natural consequences of aging.[2] These include decreased type II muscle fiber size, loss of motor units (i.e., a motor neuron and the muscle fibers it innervates), hormonal changes (i.e., a decline in serum levels of anabolic hormones like testosterone and insulin-like growth factor 1), anorexia (i.e., decreased or loss of appetite), decreased physical activity, anabolic resistance (i.e., a blunted muscle protein synthesis response to dietary protein and resistance exercise), systemic inflammation, insulin resistance, and increased body fat.[12]
Examine Database: Sarcopenia
Research FeedRead all studies
Frequently asked questions
Sarcopenia is a progressive and generalized skeletal muscle disorder characterized by a loss of muscle mass and strength and is associated with an increased risk of adverse outcomes, including falls, bone fractures, postoperative complications, physical disability, and mortality.[1][2]
There are two types of sarcopenia — primary and secondary. Sarcopenia is considered primary when it results from no other underlying cause except for age.[1] It is considered secondary when causal factors other than age are present, such as disease (e.g., cancer, advanced organ failure), malnutrition, or physical inactivity.
- History of recurrent falls
- Feeling weak
- Slow walking speed
- Difficulty rising from a chair
- Recent unintentional weight loss (> 5%)
Muscle mass, strength, and physical performance are assessed to diagnose sarcopenia.[1] Diagnosis starts with muscle strength, usually grip strength measured using a calibrated handheld dynamometer, but lower body strength may also be assessed using the chair stand test, which measures the amount of time it takes the individual to rise five times from a seated position without using their arms. If low muscle strength is determined, muscle quantity is assessed to confirm the presence of sarcopenia. Lastly, physical performance is assessed using scores on the gait speed test, the Short Physical Performance Battery, the Timed-Up and Go test, or the 400-meter walk test to determine the severity of sarcopenia.
The SARC-F is a screening tool used to quickly identify probable cases of sarcopenia. It is a self-reported questionnaire containing five components: strength, assistance in walking, rising from a chair, climbing stairs, and falls. Each component is scored from 0 to 2, with higher scores indicating greater functional impairment. A total score ≥ 4 is predictive of sarcopenia and adverse outcomes.[13][14]
To confirm the presence of sarcopenia, strength and muscle mass are assessed. The cut-off for low muscle strength is a grip strength of < 27 and < 16 kilograms for men and women, respectively, or taking > 15 seconds to complete the chair stand test.[1] The cut-off for low muscle mass, which is quantified as appendicular skeletal muscle mass divided by height squared, is < 7 and < 5.5 kilograms/meters2 for men and women, respectively.[1]
Lastly, physical performance is assessed to determine the severity of sarcopenia. The cut-off for low physical performance is a gait speed of ≤ 0.8 meters per second, a score ≤ 8 on the Short Performance Battery, taking ≥ 20 seconds to complete the Timed-Up and Go test, or taking ≥ 6 minutes to complete the 400-meter walk test.[1]
There are three main conditions that overlap with sarcopenia: frailty, malnutrition, and cachexia. Frailty is a state of increased vulnerability due to cumulative decline in multiple physiological systems[18] and involves adverse effects to physical, cognitive, and social dimensions.[19] Sarcopenia contributes to the physical aspect of frailty, but it differs from frailty because it only affects the musculoskeletal system, whereas frailty is a much broader condition.
Both malnutrition and sarcopenia are characterized by low muscle mass, but sarcopenia also includes impaired muscle function. Additionally, reduced fat mass is typically present in malnutrition, but not sarcopenia.[1]
Cachexia is described as severe weight loss and muscle wasting associated with conditions such as cancer, HIV/AIDS, or end-stage organ failure. Cachexia and sarcopenia may coexist, but the presence of the aforementioned conditions suggests that cachexia is more likely.[2] Unlike sarcopenia, cachexia is characterized by systemic inflammation, as indicated by low serum albumin and elevated C-reactive protein levels.[20] The diagnosis of cachexia also typically requires unintentional weight loss of at least 5% of body weight in the past six months.[20]
No specific drugs have been approved for the treatment of sarcopenia. Testosterone treatment may increase muscle mass and strength in older men with low serum testosterone levels (<200–300 ng/mL) and muscle weakness.[3] In addition, preliminary evidence suggests that myostatin inhibitors, which block the actions of myostatin — a protein secreted by muscle cells that inhibits protein synthesis and hypertrophy — may increase muscle mass and some measures of physical performance.[4][5] However, the medical use of myostatin inhibitors as a treatment of sarcopenia is currently limited to clinical trials.
The following supplements have been studied for the treatment of sarcopenia and have shown some efficacy in different scenarios (e.g., when combined with resistance exercise, in people with inadequate dietary intake):[6]
- Protein
- Leucine
- Creatine
- Beta-hydroxy beta-methylbutyrate
- Omega-3 polyunsaturated fatty acids
- Vitamin D
Protein is crucial for skeletal muscle growth and maintenance, and older adults display an impaired muscle protein synthesis response to the ingestion of protein,[7] so a large portion of the evidence base revolves around optimizing protein intake for the prevention and treatment of sarcopenia.
Total protein intake should ideally be 1.2–1.6 grams per kilogram of body weight per day, evenly distributed between 3–4 meals containing ≥ 0.4 grams of protein per kilogram of body weight.[6]
With respect to dietary patterns, largely consistent evidence from observational studies demonstrates that higher adherence to a Mediterranean diet is associated with better physical functioning, including lower extremity functioning, mobility, and walking speed.[8][9]
Animal-based proteins are generally higher quality than plant-based proteins because they contain adequate amounts of all the essential amino acids (EAA) and are better digested and absorbed.[21] Consequently, studies typically report a greater increase in muscle protein synthesis (MPS) following the ingestion of animal-based proteins.[22]
To overcome the lesser anabolic properties of plant-based proteins, a greater amount of protein can be consumed.[23][24] In a 3-day study in older adults (average age of 66), daily MPS rates did not differ between a high-protein (1.8 grams of protein per kilogram of body mass per day) vegan diet that provided 57% of protein as mycoprotein and a high-protein omnivorous diet.[25]
An alternative (or even additional) strategy is to combine different plant-based proteins to provide a balanced EAA profile,[26] as plant-based proteins typically contain an inadequate amount of one or more EAA.
While studies looking at acute changes in MPS are informative, they do not directly reflect longer-term changes in muscle mass and strength, which is what we’re really concerned with.
Evidence suggests plant- and animal-based protein supplements have a similar effect on changes in muscle mass and strength in older adults (≥ 50 years).[27] However, consuming an omnivorous diet and obtaining 25–50 grams of protein per day from a plant-based protein supplement is very different from consuming a vegan diet.
A 12-week study in young men demonstrated that a high-protein (1.6 grams per kilogram of body mass per day) vegan diet promoted comparable increases in leg lean mass and muscle strength as a high-protein omnivorous diet.[28] Unfortunately, a similar study has yet to be conducted in older adults, so the consequences of consuming a vegan diet on muscle mass and strength in this population remains unclear.
As it stands, the source of protein doesn’t seem to matter all that much, as long as enough total protein is consumed each day.
Resistance exercise is the most potent non-medical treatment for combatting skeletal muscle deterioration and improving health-related quality of life.[10] It’s traditionally recommended that people perform 2–3 resistance training sessions per week using relatively heavy loads (i.e., 80% of 1-repetition maximum), but more recent evidence suggests that low-load resistance training (i.e., 35–50% of 1-repetition maximum) is similarly effective for increasing muscle mass and strength when performed to volitional fatigue.[6] A combined resistance training and high-protein diet intervention seems to be more effective than either intervention alone.[11]
Resistance training can increase muscle mass, protect bone mineral density, and reduce the risk of diabetes.
Lifting weights, or resistance training, has numerous benefits to the muscles and skeleton that are uniquely attributed to this form of training.
There are some cognitive benefits associated with exercise in general, but this FAQ entry will be more focused on what resistance training can give that other forms of exercise cannot.
Resistance training?
Resistance training is a form of training where the muscles and skeleton are pit against a large force, either induced by external resistance (lifting weights) or by gravity (maximal jumping or sprinting). Resistance training tends to be focused on power, and tends to be anaerobic (intense) in nature.
Anything with maximal exertions can be considered resistance training. Things like Tennis and racquetball show some benefits as well due to some strides being full exertion, but weightlifting tends to have the most dramatic effects.
Benefits to Muscles
Most notably weight lifting, but all forms of resistance training, can increase muscle mass.
This can reduce the occurrence of sarcopenia (the age-related decline in muscle mass not associated with pro-inflammatory cytokines)[29] when elderly,[30][31] although all activity can reduce rates of sarcopenia, resistance training seems most effective.[32][33]
Benefits to Bone
Exercise in general tends to be associated with better bone mineral density and/or bone width in athletes when compared to a non-athletic control group.[34][35][36] Greater bone health and an exercise regimen are inversely associated with falls in the elderly, which suggests that exercise is a good preventative measure.[37][38][39]
It might also slightly protect against further reductions in bone mineral density in those already diagnosed with osteoporosis or osteopenia,[40] although in general activity is encouraged.[41]
In older age, those who practice Sprinting have been shown to have better bone density and size relative to jogging and walking activities.[42] Although beneficial bone adaptations seem to be better in the young, they can still occur even if one starts a physical exercise program later in life.[43]
It should be noted that swimming does not tend to increase bone density or mass, as the person is suspended in a pool of water rather than actively forcing power against gravity. It may increase bone health slighty in some persons, but is much less reliable than other forms of exercise.[41][44][45]
Health Promoting effects
Involvement in exercise for at least 150 minutes a week in associated with a reduced risk of diabetes in men, with a protective effect existing for both aerobic exercise and weight training with persons participating in both having least risk.[46]
In the case of primary sarcopenia, there is a wide range of factors that contribute to the development of the condition, which are not entirely understood and largely thought to be natural consequences of aging.[2] These include decreased type II muscle fiber size, loss of motor units (i.e., a motor neuron and the muscle fibers it innervates), hormonal changes (i.e., a decline in serum levels of anabolic hormones like testosterone and insulin-like growth factor 1), anorexia (i.e., decreased or loss of appetite), decreased physical activity, anabolic resistance (i.e., a blunted muscle protein synthesis response to dietary protein and resistance exercise), systemic inflammation, insulin resistance, and increased body fat.[12]
References
Examine Database References
- Muscle Size & Strength - Kuo YY, Chang HY, Huang YC, Liu CWEffect of Whey Protein Supplementation in Postmenopausal Women: A Systematic Review and Meta-Analysis.Nutrients.(2022-Oct-10)
- Muscle Size & Strength - Nasimi N, Sohrabi Z, Nunes EA, Sadeghi E, Jamshidi S, Gholami Z, Akbarzadeh M, Faghih S, Akhlaghi M, Phillips SMWhey Protein Supplementation with or without Vitamin D on Sarcopenia-Related Measures: A Systematic Review and Meta-Analysis.Adv Nutr.(2023-Jul)
- Upper Body Strength - Kamińska MS, Rachubińska K, Grochans S, Skonieczna-Żydecka K, Cybulska AM, Grochans E, Karakiewicz BThe Impact of Whey Protein Supplementation on Sarcopenia Progression among the Elderly: A Systematic Review and Meta-Analysis.Nutrients.(2023-Apr-23)
- Body Fat - Su H, Zhou H, Gong Y, Xiang S, Shao W, Zhao X, Ling H, Chen G, Tong P, Li JThe effects of β-hydroxy-β-methylbutyrate or HMB-rich nutritional supplements on sarcopenia patients: a systematic review and meta-analysis.Front Med (Lausanne).(2024)