FEATURE 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, vita-min D) can improve skeletal muscle re-generation 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 com-pared to younger adults. This will affect nutrients getting to the SC and depend-ing on the distance, may affect the func-tion 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 synthe-sis. The combination of dietary strategies and the beneficial effects of exercise represents an intervention that can alle-viate 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 tis-sues are mechanically loaded and many of their secreted factors are regulated by the load. Exercise is mechanical loading and has beneficial effects on many sys-tems 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 age 10 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 www.Cndoctor.ca AGING AND COGNITION Sarcopenia Life and longevity, part 6 BY DR. DON FITZ-RITSON, DC L For muscle cells to respond effectively to interventions (i.e. exercise or 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. 14 Chiropractic and Naturopathic Doctor May/June 2021 Photo: © Cherries / Adobe Stock et’s look at some of the fac-tors contributing to sarco-penia as it progresses with aging. Sarcopenia is the age-related loss of skeletal muscle mass and strength. 1 Loss of muscle strength af-fects a person’s independence and con-tributes to falls and other health issues, thereby affecting the finances of health-care systems worldwide. Sarcopenia contributes to decreased ability for the aged muscle to regenerate, repair and remodel without intervention. The esti-mated prevalence of sarcopenia is be-tween five and 40% in the general pop-ulation, 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 dec-ade 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, com-bined exercise and nutrition improve muscle strength to a more prominent degree than exercise or nutrition alone. 5 RESPONDING TO INTERVENTIONS
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