The general belief is that hearing, vision, heart function, and cognition decline with age. Many older adults use multiple dietary or medical interventions for most of the functional decline that happens with age; however, loss of muscle mass and muscle strength that occurs with aging is often left unnoticed. In large part, aged people don’t realize that their difficulty climbing the stairs or getting out of the chair could be due to ‘SARCOPENIA’. 

Sarcopenia impacts millions of older adults, and it is critical to prevent or postpone as much as possible the onset of Sarcopenia. 

In this article, we will review the nature of Sarcopenia, its causes, symptoms, consequences, and the ways; to manage this condition to enhance survival and reduce the demand for long-term care. 

 

IMPORTANCE OF SKELETAL MUSCLES

Skeletal muscle, which accounts for almost half of the body mass; plays diverse crucial physical and metabolic roles in humans. Apart from maintaining our body posture, allowing mobility of bones, and stabilizing our joints, skeletal muscle mass helps in regulating the homeostasis of glucose metabolism. Studies suggest that skeletal muscle deteriorates quantitatively and qualitatively with aging.

Studies suggest that by the age of 40, skeletal muscle mass and skeletal muscle strength decline in a linear fashion. Since muscle tissue is linked with diverse physical and metabolic roles in the body, a significant loss of muscle mass and strength has profound consequences on the older adult and may cause adverse health outcomes.

While the aging process is inevitably-accompanied by attenuation of functions in many organs, muscle tissue also deteriorates with aging, but this need not be inevitable.

 

DEFINITION OF SARCOPENIA

Sarcopenia refers to involuntary loss of muscle mass or muscle strength and physical performance (which are compromised due to aging).

The term, ‘Sarcopenia’ was coined by Rosenberg to describe skeletal muscle mass loss. The term is derived from the Greek word, ‘sarx’ which means ‘flesh’ and ‘penia’ which means ‘loss’.

 

IS SARCOPENIA THE SAME AS FRAILTY?

Both the conditions are increasingly prevalent with age. While there is overlap between the two conditions, Sarcopenia and Frailty, remain distinguishable. Sarcopenia is particularly concerned to musculoskeletal system (loss of muscle mass), whereas, Frailty encompasses a broader range of dysfunction than Sarcopenia (multisystem impairment).

 

HOW TO KNOW IF YOU HAVE SARCOPENIA?

Check hand grip strength while lifting or carrying 10 pounds.
Assistance needed in walking across a room.
Difficulty experienced while rising from bed, chair, and difficulty experienced on a flight of 10 stairs.
Check leg extension or flexion strength.
Deteriorated walking speed.

CONSEQUENCES OF SARCOPENIA

Poor body balance, weak bone, loss of independence, hospitalization, mobility limitations, reduced strength of the hip and lower leg muscles. Increased risk of falls, fractures, osteoporosis, injuries, finding daily activities tough to perform, and diminished quality of life.

 

CAUSES OF SARCOPENIA

Multiple factors may contribute to the development of Sarcopenia. Although Sarcopenia is basically an age-related factor, it is also influenced by genetic and lifestyle factors.

 

PROTEIN DEFICIENCY: Declines in adequate protein and calorie intake with aging. Our body responds to protein deficiency by taking amino acids (building blocks of proteins) away from muscle tissue and other body areas. This process, in which the body basically metabolizes itself, called catabolism leads to muscle loss and weakness. Protein-restricted diets are sometimes recommended for those with chronic kidney and liver insufficiency.

LOW-GRADE INFLAMMATION: Aging is associated with chronically increased levels of pro-inflammatory cytokines, like interleukins. Higher levels of inflammatory markers are associated with a greater risk of losing muscle mass and muscle strength.

ANABOLIC RESISTANCE: When stimulated with resistance training, insulin, and essential amino acids, muscle protein synthesis increases. But the rate of protein synthesis varies in young and old individuals. In the elderly, there is a reduced response to anabolic stimuli, termed ‘anabolic resistance’.

IMPAIRED REGENERATION OF MUSCLES: Skeletal muscle regeneration is dependent on satellite cells which are the primary stem cells. The reduced stem cell function in the elderly results in impaired regeneration of muscles.

INACTIVITY: Inactivity or lack of exercise, prolonged bed rest (which results in loss of mobility), decreased activity levels.

 

INCREASED FAT MASS: The loss of muscle mass and muscle strength coupled with low physical activity levels decrease total energy expenditure, which ultimately results in the accumulation of fat mass, especially visceral fat. Loss of muscle mass will produce insulin resistance which promotes metabolic syndrome. An increase in body fat may lead to the higher secretion of pro-inflammatory markers that further promote insulin resistance as well as direct catabolic effects on muscles.

LOW TESTOSTERONE LEVELS: The serum concentration of male sex hormone testosterone levels decline with age. This is even more common in hypogonadal men, a condition in which gonads produce little or no testosterone. The low testosterone will cause accelerated loss of muscle mass and strength.

DECLINE IN INTAKE OF NUTRITION: Decreased nutrient intake, especially protein and calorie intake or overnutrition can lead to Sarcopenic obesity (obesity with decreased muscle mass and function).

 

Decrease in neurological signals between the brain and the muscle, gastrointestinal disorder, rheumatoid arthritis, osteoporosis, kidney disease, frailty, reduced intake of vitamin D, and people with comorbidities are all contributing factors to Sarcopenia.

 

MULTIPLE INTERVENTION CHOICES FOR SARCOPENIA

Eat a healthy, balanced diet.

Treat underlying causes like malnutrition, gastrointestinal disorders.

Choose a range of physical exercises that targets the whole body – legs, hips, abdomen, shoulders, arms.

Limit alcohol consumption along with quitting smoking.

Consume healthy nutrients like omega-3 fatty acids, vitamin D, Whey Protein, leucine.

 

Maintenance of muscle mass and muscle strength is critical for the preservation of physical activity and reducing the risks of falls and fractures in older age.