By Paul Savage, MD, FAARM, ABAARM – Founder and Chief Medical Officer | Power2Practice
Sarcopenia is one of the most significant causes of functional decline, frailty and loss of independence in older adults. Defined by reductions in both muscle mass and muscle function/strength, the cause of sarcopenia is truly multifactorial. Hormonal changes, disease triggers, inflammatory pathway activation, decline in neuromuscular junctions and satellite cells, adipose infiltration, poor nutrition and reductions in physical activity are all thought to contribute.
Sarcopenia Begins Earlier Than Imagined
Sarcopenia may begin to develop as early as age 30, when body weight gain and fat accumulation masks the early visual signs of muscle loss. After forty, especially with declining hormone levels, loss of muscle and strength accelerate noticeably so that by late middle age, functional consequences such as weakness, frailty, poor coordination, reduced endurance, loss of vitality, erosion of life quality and independence arise and continue to worsen with each passing decade. Without intervention, skeletal muscle mass and skeletal muscle strength continue to decline in a linear fashion, with up to 50% of mass being lost by the 8th decade of life.(1)
In our sedentary society, lack of physical activity, poor nutritional balance and changing hormones are the top reasons for early-middle age lean tissue decline. With targeted lifestyle changes, sarcopenia is preventable and even totally reversible. During early-middle age, preventative measures should focus on exercise that includes resistance training, optimizing nutrition and hormone balance.
Sarcopenia is accelerated with lack of physical activity, especially lack of resistance exercise, which places appropriate load on fast-twitch muscle fibers. It is a primary reduction in these type 2 fast-twitch muscle fibers (which are responsible for strength), along with adipose infiltration that is noted in sarcopenia. In addition, skeletal precursor cells, or satellite cells, are also reduced as a natural part of aging. These cells are normally activated and begin the process of muscle repair in response to the stress of heavy muscle use, such as with weight-bearing activities or in response to injury.(2)
A properly designed resistance training program can increase motor neuron firing rates, improve muscular recruitment and create a more efficient motor unit for long-term muscle health while supporting healthy protein synthesis via satellite cells. For these reasons, a regular exercise regime that includes resistance strength training is critical to preventing sarcopenia.
How much exercise: Adults should participate in 45-minutes of appropriate exercise that includes weight resistance training at least 4 times per week—working a different major muscle group each session. The major muscle groups to target include: back, chest, shoulders, trapezius, biceps, triceps, forearms, abs, quadriceps and hamstrings.
For those without access to a gym: Resistance training can be accomplished with the use of therapy bands, therapy balls or the use of body weight and balancing techniques. If working with previously-sedentary adults over age 65, start with 20-minutes of exercise per session, working up to 45-minutes per session as cardiorespiratory and muscular endurance improves. Beginning with a shorter duration per session will still provide benefits while positively impacting adherence.
Inadequate and imbalanced caloric intake is yet another significant factor in the development of sarcopenia. Age-related lowered responsiveness to internal cues of hunger and thirst, changes in the oral cavity that make chewing and digesting food more difficult and impaired digestion and absorption of nutrients set the stage for fatigue and muscle wasting.
Reliance on processed foods is yet another factor, especially for adults with mobility issues. These foods are abundant in carbohydrate calories, yet lack balanced ratios of protein, carbohydrates, healthy fats, vitamins and minerals necessary to sustain healthy skeletal muscle. Overnutrition that leads to sarcopenic obesity is just as significant a factor as undernutrition.
Adequate nutrition to prevent sarcopenia includes:
- An overall increase in balanced calories
- More protein with a focus on BCAAs – at 40% of caloric intake
- More complex carbohydrates – at 30% of caloric intake
- More healthy fats – at 30% of caloric intake
All of these nutrients, including fruits and vegetables, may be consumed in a breakfast protein shake. When it comes to using a protein powder, recommend products that contain branched-chain amino acids (BCAAs), such as whey, which also tends to be easier to digest. One study found whey protein to be superior for preserving lean body mass in older adults.(3) If whey is not well-tolerated, a plant-based protein with BCAA dietary supplements should be used.
Aging is associated with natural changes in hormone levels, including decreased testosterone (T), growth hormone (GH) and insulin-like growth factor (IGF-1). Decreased concentrations of these hormones are linked to the development of sarcopenia.
- GH and IGF-1 play a significant role in protein metabolism.
- GH and T are required for protein maintenance.
- IGF-1 levels are positively correlated with muscle protein synthesis rates, specifically actin and myosin filaments and myosin heavy chain synthesis. (4)
A sustained decrease in these hormones is related to an increase in adipose and overall decrease in lean muscle mass. There is a great deal of debate around modulation of GH levels, so it is best to work on balancing testosterone levels in both men and women.
Reducing High Cortisol
Cortisol, a potent protein catabolism stimulus and immune-system depressor, naturally increases slightly with age. Those with high stress levels and thus, elevated cortisol, may experience an increase in adipose production and storage above and beyond the normal age-associated levels. High cortisol may also decrease resistance to illness and therefore, reduce physical activity. In the presence of obesity, GH secretion is particularly depressed with a blunted and disorderly response to oral glucocorticoid suppression.
These findings place particular emphasis on the importance of maintaining a healthy body weight and managing stress throughout the lifespan to prevent sarcopenia.
Inflammation is linked to a number of chronic diseases such as cancer, heart disease and a wide array of autoimmune disorders. A study (2) of serum levels of the inflammatory cytokine interleukin-6 and its relationship to muscle strength in older women demonstrated a steeper decline in walking ability, and a higher risk of developing physical disability, explained in part by a parallel decline in skeletal muscle strength.
Signs of inflammation include stiffness, pain, swelling, weight gain and fatigue, just to name a few. It is clear that high inflammatory states go hand-in-hand with the development of sarcopenia and that patients should make necessary lifestyle changes to lower inflammation naturally by:
- Reducing weight as necessary
- Healing the gut
- Modifying diet
- Addressing stress and adrenal dysfunction
- Getting enough sleep
- Avoiding pesticides, pollutants and heavy metals
- Balancing the hormones as necessary
Minimizing Sarcopenia in Already-Active Adults
While reductions in physical activity and poor nutritional status are prime factors in the development of sarcopenia, there are certain age-related molecular components that cannot be controlled by exercise and diet. Recent molecular findings related to apoptosis, mitochondrial decline and the angiotensin system in skeletal muscle have highlighted biological mechanisms that may be contributory to the sarcopenia experienced by physically-active adults. (2)
Some important studies have helped shed light on these molecular triggers:
- Mitochondrial function and biogenesis appears to be altered in the skeletal muscles of older adults.
- Age-related changes in the angiotensin system were recently identified to play a crucial role in skeletal muscle healing and disuse atrophy.
- Apoptosis, or cell death, may also play an important role. Preliminary studies of proteins associated with apoptosis showed an upregulation in those older adults with lower thigh muscle volume and slower gait speed, suggesting that apoptosis may contribute to this muscle decline.
- And even newer evidence suggests altered transcriptional regulation of mRNA and translation of proteins negatively impact proteins important in myogenesis. (2)
Adequate nutrition and exercise will remain the gold standard therapy for sarcopenia, yet certain interventions may help prolong muscle strength and endurance by targeting multiple biological pathways, especially among already-active older adults.
Active Adults Must Pay Extra Attention to Protein & Eat Enough of the Right Kinds
Research is showing that adults age 65 and older need higher levels of protein, especially adults that are engaged in strength training exercise. 1 – 1.2 g/kg a day is ideal for all adults over age 65, yet healthy adults who are active and showing signs of sarcopenia should consume 1.2 to 1.5 g/kg a day. To figure out how much protein is needed by individual person, take their weight in pounds and multiply it by 0.45. Then multiply by 1.2 to reach the recommended grams of protein per day.
While it’s best to eat protein-rich foods in the morning and within 30-minutes after strength training exercise, it is still beneficial to consume protein at other times of the day. At this stage of life, quantity matters more than timing of consumption.
Furthermore, the amino acid leucine has been shown to help preserve muscle, so it is further beneficial to eat protein that is higher in leucine, such as: beef, lamb, pork, poultry, fish, eggs and milk products (if well tolerated). Leucine is also found in soybeans, other beans, nuts and seeds, but to lesser extent than animal sources.
Active older adults may benefit from supplemental creatine, which is used by type 2 fast-twitch muscle fibers as a primary fuel source during short, intense exercise such as weight lifting and sprinting. Studies have found that when creatine is given to older adults participating in resistance training exercise, it helps increase lean body mass and strength. (4-6)
Novel pharmaceutical interventions that target multiple biological pathways are also being developed, yet dietary interventions and resistance strength training are most advisable for preventing sarcopenia throughout the entire lifespan.
About the Author:
Dr. Paul Savage founded Power2Practice in 2011 and is currently serves as the Chief Medical Officer. He graduated from the University of Michigan Medical School in Emergency Medicine and later earned his board certification in Integrative Medicine at George Washington University.
Since 2004, he has practiced integrative medicine exclusively and is considered by many as one of the world’s foremost authorities in the area of integrative metabolic medicine (IMM), including bioidentical hormone therapy.
Dr. Savage is currently Founder and President of Chicago Integrative Care where he practices medicine. He continues to lecture worldwide and frequently provides expert insights on hormone therapy to major news media.
- Metter EJ, Conwit R, Tobin J, Fozard JL. Age-associated loss of power and strength in the upper extremities in women and men. J Gerontol A Biol Sci Med Sci. 1997; 52:B267–B276. [PubMed: 9310077]
- Ferrucci L, Penninx BW, Volpato S, et al. Change in muscle strength explains accelerated decline of physical function in older women with high interleukin-6 serum levels. J Am Geriatric Soc. 2002; 50:1947–1954. [PubMed: 12473005]
- Walston JD. Sarcopenia in older adults. Current opinion in rheumatology. 2012;24(6):623-627. doi:10.1097/BOR.0b013e328358d59b.
- Brose A, Parise G, Tarnopolsky MA. Creatine supplementation enhances isometric strength and body composition improvements following strength exercise training in older adults. J Gerontol A Biol Sci Med Sci. 2003 Jan;58(1):11-9.
- Gotshalk LA, Volek JS, Staron RS, et al. Creatine supplementation improves muscular performance in older men. Med Sci Sports Exerc. 2002 Mar;34(3):537-43.
- Chrusch MJ, Chilibeck PD, Chad KE, Davison KS, Burke DG. Creatine supplementation combined with resistance training in older men. Med Sci Sports Exerc. 2001 Dec;33(12):2111-7.