Sarcopenia: Life and longevity, part 6

Let’s look at some of the factors contributing to sarcopenia as it progresses with aging. Sarcopenia is the age-related loss of skeletal muscle mass and strength.¹ Loss of muscle strength affects a person’s independence and contributes to falls and other health issues, thereby affecting the finances of healthcare systems worldwide. Sarcopenia contributes to decreased ability for the aged muscle to regenerate, repair and remodel without intervention. The estimated prevalence of sarcopenia is between five and 40% in the general population, accompanied by an exponential decline with increasing age. The loss of muscle mass begins from middle-age (~1%/year), and in severe instances can lead to a loss of ~50% by the 8-9th decade of life.² Also, people with sarcopenia have a higher risk of falls and fractures compared to people of the same age without sarcopenia, increased risk of morbidity (chronic diseases) in addition to all-cause mortality.³

A couple of studies address some of the main problems that contribute to sarcopenia: Reduced muscle mass with aging is mainly attributed to smaller type II muscle fibre size and the increase in muscle mass following prolonged fast resistance-type exercise training can be attributed entirely to specific type II muscle fibre hypertrophy.⁴ Also, combined exercise and nutrition improve muscle strength to a more prominent degree than exercise or nutrition alone.⁵

Responding to interventions
For muscle cells to respond effectively to interventions (i.e. exercise or nutrition) we must take a holistic view of the person. First of all, they are aging and all systems are in decline. Certain aspects of muscle cell recovery involve cross-talk between the immune system and muscle cells. With aging this repair capacity is depressed, contributing to sarcopenia. Nutritional studies demonstrate that nutrients (amino acids, Omega-3, vitamin D) can improve skeletal muscle regeneration by targeting key functions of immune cells, muscle cells or both.⁶ Muscle cells are in close contact with stem cells and are called satellite cells (SC). They maintain muscle cell health and are essential for regeneration throughout life. Any disruption with the SC pool will affect muscle mass. Aging affects the capillarization of muscle cells and the distance between type II fibre SC and capillaries is greater in older compared to younger adults. This will affect nutrients getting to the SC and depending on the distance, may affect the function of the SC. Muscle cells, in extreme cases, therefore, may lack the ability to regenerate or hypertrophy with exercise.¹

There are exosomes (small vesicles), located in muscle fibres that can regulate muscle regeneration and protein synthesis. The combination of dietary strategies and the beneficial effects of exercise represents an intervention that can alleviate the progression of sarcopenia.⁷ Muscle does not act on bone in only a mechanical way to propel the movement of the organism. Contracting muscle acts as a secretory organ, regulating metabolism. Both bone and muscle tissues are mechanically loaded and many of their secreted factors are regulated by the load. Exercise is mechanical loading and has beneficial effects on many systems and may explain how exercise contributes to improvement. Lack of loading, that is, no exercise can have detrimental effects.⁸ The skeletal muscle secretome releases various molecules that affect bone development, cartilage, adipose tissue, and are also likely to participate in this control loop. The understanding of this system will enable us to define new levers to both prevent/treat sarcopenia.⁹

Nerve muscle interactions are also negatively affected with increasing age¹⁰ and this, like all other systems which are in decline, will have implications on the development of effective therapies.¹¹ There is some evidence that the long spinal tracts may also be involved. When the corticospinal track was tested via muscle monitoring, there were significant differences between sarcopenic and non-sarcopenic older adults.¹²  This indicated that the nerve supply was decreased in sarcopenic adults. Sarcopenia, therefore, is a complex condition of aging that involves every system of the body, including physical inactivity, endocrine factors, neuromuscular compromise to mitochondrial dysfunction are, all interdependent.¹³

Making effective changes
Malnutrition and poor physical performance are both conditions that increase in prevalence with age. Digestive enzymes also decrease with age, leading to maldigestion and malnutrition.¹⁴ Some studies have indicated that muscle power is more impacted by nutritional status than muscle strength. This would imply that the type II muscle fibre, which is affected by certain nutrients, is involved.¹⁵ Physical training has a synergistic influence with diet protein. Physical training improves muscle performance, muscle strength and prevents muscle wasting. Physical training combined with an increased amount of protein in the diet results in increased muscle mass.¹⁶ The best physical training approach would be a combined exercise program consisting of both resistance-type and endurance-type exercises for skeletal muscle mass and function and to improve physical performance and quality of life.¹⁷ To treat the age-related chronic low-grade inflammation which is assumed to contribute to the development of sarcopenia, Omega-3 polyunsaturated fatty acids (PUFAs) would be an additional therapeutic agent for sarcopenia ¹⁸ and should be included.

There are other strategies that can help – and in the case of the more severe sarcopenic individuals one strategy first helps by raising their muscles to functioning levels? Whole-body vibration is safe and can be used at very low frequencies and still have therapeutic effects. A recent study showed that there were positive effects of whole-body vibration – intervention on improving the skeletal muscle mass index, physical fitness, and quality of life of sarcopenic older people living in institutions.¹⁹ Another study found that frail, elderly people improved their levels of physical functionality²⁰ and regained muscle strength, reducing the risk and incidence of falls, frailty, and fracture risks.²¹

There’s also a new training method called blood flow restriction training (BFR), which uses light weights with restriction cuffs on the arms and thighs. Because blood flow is being restricted, the lighter weights achieve similar results compared to using heavier weights. This would be very effective for people with sarcopenia just beginning an exercise program. BFR training is a novel training method that has a significant impact on muscle strength²² and could be included in a program for older adults with profound muscle weakness and mobility limitations.²³ However, certain patients with heart conditions may require careful monitoring.

Because we are living with COVID-19, I encourage everyone to read the following referenced paper. The authors outline how measures such as quarantine, isolation, and social distancing leading to an extended time at home contribute to impaired sleep, increased stress, anxiety, cognitive decline and depression.²⁴ All of these affect eating patterns and physical activities/exercise, which promote increased body fat, CVD, inflammation, diabetes and sarcopenia. CVD, diabetes, and elevated body fat are associated with a greater risk of COVID-19. To mitigate these risk factors, and to prevent more chronic symptoms from developing for the sarcopenic person, the authors offer several home-based strategies including resistance exercise, higher protein intakes, and good diets and supplementation.  These home-based strategies will also improve sleep, stress, anxiety, cognitive decline and depression.

References

1.  Joanisse S, et al. Skeletal Muscle Regeneration, Repair and Remodelling in Aging: The Importance of Muscle Stem Cells and Vascularization. Gerontology. 2017;63(1):91-100. 
2. Wilkinson J, et al. The Age-Related Loss of Skeletal Muscle Mass and Function: Measurement and Physiology of Muscle Fibre Atrophy and Muscle Fibre Loss in Humans. Ageing Res Rev. 2018 Nov: 47: 123-132. 
3. Yeung S, et al. Sarcopenia and Its Association With Falls and Fractures in Older Adults: A Systematic Review and Meta-Analysis. J Cachexia Sarcopenia Muscle. 2019 Jun;10(3):485-500. 
4. Nilwik R, et al. The decline in skeletal muscle mass with aging is mainly attributed to a reduction in type II muscle fiber size. Exp Gerontol. 2013 May; 48(5): 492-8.
5. Buckinx F, et al. Relevance to assess and preserve muscle strength in aging field. Prog Neuropsychopharmacol Biol Psychiatry. 2019 Aug 30; 94: 109663.
6. Domingues-Faria C, et al. Skeletal Muscle Regeneration and Impact of Aging and Nutrition. Ageing Res Rev. 2016 Mar: 26: 22-36. 
7. Rong S, et al. The Mechanisms and Treatments for Sarcopenia: Could Exosomes Be a Perspective Research Strategy in the Future? J Cachexia Sarcopenia Muscle. 2020 Apr; 11(2): 348-365. 
8. Bonewald L. Use It or Lose It to Age: A Review of Bone and Muscle Communication. Bone  2019 Mar: 120: 212-218. 
9. Tagliaferri C, et al. Muscle and bone, two interconnected tissues. Ageing Res Rev. 2015 May; 21: 55-70. 
10.  Morat T, et al. Neuromuscular function in different stages of sarcopenia. Exp Gerontol. 2016 Aug; 81: 28-36. 
11. Clark B. Neuromuscular Changes With Aging and Sarcopenia. Clin Interv Aging. 2017 Jun 13; 12: 955-961. 
12. Gennaro F, et al. Corticospinal Control of Human Locomotion as a New Determinant of Age-Related Sarcopenia: An Exploratory Study. J Clin Med . 2020 Mar 6; 9(3): 720. 
13. Tournadre A, et al. Sarcopenia. Joint Bone Spine. 2019 May: 86 (3): 309-314.
14. Löhr J-M, et al. The ageing pancreas: a systematic review of the evidence and analysis of the consequences. J Intern Med. 2018 May;283(5):446-460.
15. Ramsey K, et al. Malnutrition is associated with dynamic physical performance. Aging Clin Exp Res. 2019 Aug 19: 35-41. 
16. Turżańska K, et al. Protein and physical activity in prevention and treatment of sarcopenia.  Wiad Lek. 2019; 72(9 cz 1):1660-1666.
17. Strasser B, et al. Role of Dietary Protein and Muscular Fitness on Longevity and Aging. Aging Dis. 2018 Feb 1; 9(1): 119-132.
18. Dupont J, et al. The Role of omega-3 in the Prevention and Treatment of Sarcopenia. Aging Clin Exp Res.  Jun 2019 :31 (6): 825-836. 
19. Chang S, et al. The preliminary effect of whole-body vibration intervention on improving the skeletal muscle mass index, physical fitness, and quality of life among older people with sarcopenia. BMC Geriatr. 2018 Jan 17;18(1):17. 
20. Wadsworth D, et al. Effects of Whole-Body Vibration Training on the Physical Function of the Frail Elderly: An Open, Randomized Controlled Trial. Arch Phys Med Rehabil . 2020 Mar 4; S0003-9993(20): 30144-1. 
21. Bemben D, et al. Relevance of Whole-Body Vibration Exercises on Muscle Strength/Power and Bone of Elderly Individuals. Dose Response. 2018 Dec 6; 16(4): 1559325818813066. 
22. Beckwée D, et al. Exercise Interventions for the Prevention and Treatment of Sarcopenia. A Systematic Umbrella Review. J Nutr Health Aging. 2019; 23(6): 494-502. 
23.  Cook S, et al. Blood Flow Restricted Resistance Training in Older Adults at Risk of Mobility Limitations. Exp Gerontol, 2017 Dec. :99: 138-145. 
24. Kirwan R, et al. Sarcopenia during COVID-19 lockdown restrictions: long-term health effects of short-term muscle loss. GeroScience. 2020 Dec; 42(6): 1547–1578.

Dr. Don Fitz- Ritson is a chiropractor and a rehab specialist. He was an Assistant Professor at CMCC. He published 17 papers and 3 chapters on chiropractic.He co-invented a laser and it received 7 Health Canada Approvals. He is focused on helping the aging population live better lives.