It is characterized by normal aging, a decrease in bone and muscle mass, and an increase in adiposity. Decrease in muscle mass and decrease in muscle strength lead to fracture risk, fragility, decreased quality of life and loss of independence. These changes in the musculoskeletal system reflect the aging process and the consequences of reduced physical activity. Muscle wasting in frail elderly people is referred to as ‘sarcopenia’.
This disorder leads to a higher incidence of falls and fractures and a functional decline. Functional sarcopenia or age-related musculoskeletal changes affect 7% of the elderly over 70 years of age, and the rate of deterioration increases over time and affects more than 20% of the elderly up to age 80 Power decreases by 1.5% per year, and this accelerates after 60 years of age up to 3% per year. These rates are considered to be higher for sedentary individuals and twice as high for men compared to women. However, research shows that, on average, men have more muscle mass and survive shorter than women. This potentially makes sarcopenia a larger public health problem among women than men.
Skeletal muscle strength (capacity to generate force) also increases with aging. decreases. This depends on lifestyle choices as well as genetic, nutritional and environmental factors. This decrease in muscle strength causes problems in physical activity and daily life activity. The total amount of muscle fiber decreases due to the decreased capacity of cells to produce protein. All major muscle groups such as deltoids, biceps, triceps, hamstrings, gastrocnemius (calf muscle) have a reduction in the size of muscle cells, fibers and tissues with a total loss of muscle strength, muscle volume and muscle strength.
Wear and tear or waste occurs in the protective cartilage of the joints. Cartilage normally functions as a shock absorber and a slip agent that prevents frictional injuries of the bone. There is stiffening and fibrosis of connective tissue elements that reduce the range of motion and affect movements by making them less efficient. Telomere shortening occurs as part of the normal cell division process. DNA is more exposed to chemicals, toxins and waste products produced in the body. This whole process increases the vulnerability of cells.
With aging, toxins and chemicals are formed in the body and tissues. As a whole, this harms the integrity of the muscle cells. Physical activity also decreases with age due to the change in lifestyle. However, physiological changes in the muscles are exacerbated by age-related neurological changes.Most of the muscle activities become less effective and less sensitive with aging as a result of a decrease in nerve activity and nerve conduction.
A study was conducted by Williams et al. This study suggests that limb muscles are 25-35% shorter and less sensitive in healthy elderly individuals compared to young adults, evaluating muscle samples from both old and young adults. Additionally, the overall fat content of the muscles was also higher in the elderly population, suggesting the transformation in normal remodeling with age.
Age-related musculoskeletal changes are much more pronounced in fast-twitch muscle fibers compared to slow-twitch muscle fibers. With aging, the total water content of the tissue decreases and the loss of hydration contributes to inelasticity and hardness. Changes in basal metabolic rate and slowing metabolism (as part of the physiological aging process) cause muscle changes. This leads to the replacement of proteins with adipose tissue (this makes the muscle less efficient).
Hormonal disorders can affect the metabolism of bones as well as muscles. Studies show that menopause in women indicates a worsening of the musculoskeletal system changes due to estrogen deficiency, which is necessary for the remodeling of bones and soft tissues. In the case of diabetes, certain systemic conditions such as vascular disorders or metabolic disorders affect tissue remodeling as the rate or volume of nutrition is compromised to regenerate cells.
It is very important to control pathological processes in order to optimize recovery and restore the potential of the musculoskeletal system. Essential vitamins such as vitamin D and vitamin C play an important role in the functional growth of muscles and bones. Lack of certain minerals such as calcium, phosphorus and chromium can be the result of age-related digestive problems. Therefore, it causes imbalance in the production of certain hormones such as calcitonin and parathyroid, which regulate the serum concentration of vitamins and minerals (due to tumors that are quite common in the elderly) or reduced absorption from the gut.
Age-related deterioration of muscle strength and balance control mechanisms has been associated with decreased performance in functional tasks. Comparing the isometric strength levels of the same muscle group, the loss of strength begins earlier in women than in men. It is reported that women are weaker than men in the absolute strength of various muscle groups at all stages of life. Various studies indicate that women have a longer life span, so the prevalence of disability among women is higher than men and is marked by advancing age.
Body Composition Changes in Old Age
The human body is made up of fat, lean tissue (muscles and organs), bones and water. After the age of 40, people begin to lose their lean tissue. Body organs such as the liver, kidneys, and other organs begin to lose some of their cells. This decrease in muscle mass is associated with weakness, disability, and morbidity.
The shrinking tendency occurs in different gender groups and in all races. Height loss is associated with aging changes in bones, muscles, and joints. Studies show that people lose almost half an inch (about 1 cm) every 10 years after age 40. After the age of 70, height loss is even faster. These changes can be prevented by following a healthy diet, staying physically active, and preventing and treating bone loss.
Changes in total body weight vary for men and women as men gain weight by the age of about 55 and then begin to lose weight later in life. This may be related to the decrease in the male sex hormone testosterone. Women usually gain weight by the age of 67-69 and then begin to lose weight. Later in life, weight loss occurs partly because fat replaces lean muscle tissue and fat is lighter than muscle. Studies have also shown that older people can have almost a third more fat compared to their youth. Adipose tissue rises towards the center of the body, including the internal organs.
Author: Ozlem Guvenc Agaoglu