[KoK! Health] One Step Closer to 'Well Aging'... Preventing Sarcopenia with Exercise and Protein Intake

Asia Economy DB

[Asia Economy Reporter Kim Young-won] During the holiday season, when visiting your hometown and spending time with your parents after a long time, you may notice that their walking speed has slowed down or they have difficulty lifting objects compared to before. This is a natural phenomenon caused by muscle loss that occurs as anyone ages, but it should not be taken lightly or neglected.

When sarcopenia, a condition characterized by decreased muscle strength and impaired physical function, occurs, the risk of falls and fractures increases, making it difficult to maintain daily living functions and leading to other complications. The World Health Organization (WHO) has defined sarcopenia as a disease, considering that the mortality rate of people with sarcopenia is up to twice as high as those without it. As new concepts like "well-aging," which means aging healthily, gain attention, Professor So Yoon-su from the Department of Rehabilitation Medicine at Kyung Hee University Hospital explains sarcopenia, whose prevalence is increasing, for a healthy 100-year life.

What is sarcopenia?

Sarcopenia is a compound word derived from the Greek words "sarco," meaning muscle, and "penia," meaning loss. It is a disease characterized not only by a decrease in muscle mass mainly due to aging but also by a decline in muscle strength or physical motor function. In 2016, WHO officially registered sarcopenia as a disease code (M62.84) in the 10th revision of the International Classification of Diseases (ICD-10), and Korea has considered it a disease since 2021 by including the diagnostic code in the 8th revision of the Korean Standard Classification of Diseases. According to the Korean Frailty Cohort Study targeting community-dwelling elderly aged 70 to 84 nationwide, 21.3% of men and 13.8% of women were diagnosed with sarcopenia.

What causes sarcopenia?

The biggest cause of sarcopenia is aging. Other causes include fractures due to osteoporosis, neurological diseases such as stroke and dementia, internal diseases like diabetes and chronic kidney disease, and cancer. For example, in diabetes, high blood sugar levels cause poor blood flow in microvessels, which results in inadequate nutrition supply to peripheral muscles and nerves, making muscle formation difficult. In arthritis, pain leads to reduced movement, increasing the prevalence of sarcopenia.

How is sarcopenia diagnosed?

Self-testing is possible as a primary diagnosis for sarcopenia. If the calf circumference is less than 34 cm for men and 33 cm for women, and the sarcopenia self-diagnosis questionnaire (SARC-F) score is 4 or higher, it is advisable to visit a hospital for further examination. In hospitals, sarcopenia is diagnosed by evaluating both the quantity and quality of muscles through measurements of skeletal muscle mass, grip strength, and physical motor function. Skeletal muscle mass is measured using dual-energy X-ray absorptiometry (DXA), which is also used for bone density measurement, and bioelectrical impedance analysis (BIA) such as InBody. When measured by DXA, sarcopenia is diagnosed if the muscle mass is 7.0 kg/m² or less for men and 5.4 kg/m² or less for women; when measured by BIA, the thresholds are 7.0 kg/m² for men and 5.7 kg/m² for women. Additionally, if grip strength is less than 28 kg for men and 18 kg for women, combined with assessments of physical motor functions such as walking speed, sarcopenia is diagnosed.

How is sarcopenia treated?

The most representative treatment and prevention method is exercise. Since there is currently no medication for sarcopenia, appropriate management for prevention is crucial. Among various exercises, the core is muscle-strengthening exercises. These should be performed at least twice a week, starting at a low intensity (40-50% of 1RM, the maximum weight one can lift once) and gradually increasing the intensity every 2-3 weeks. While muscle-strengthening exercises are important, it is recommended to combine various types of exercises such as aerobic exercise, resistance training, flexibility exercises (stretching), and balance training. The most important factor is to exercise consistently for at least three months to achieve improvements in muscle strength and hypertrophy.

For elderly people who find exercise difficult, band exercises with relatively low difficulty are recommended. In a study where elastic band exercises involving quick pulling and slow releasing were performed for 12 weeks by elderly people aged 65 and older who did not regularly exercise, muscle strength such as grip strength increased by up to 49%, and the ability to perform simple movements like walking improved by 33%. However, this exercise must be done consistently at least three times a week, with each set consisting of 12 repetitions and three sets per session to be effective. Additionally, wall squats, where one leans against a wall to perform squats, allow those who find regular squats difficult to engage in lower body exercises.

What are the preventive measures for sarcopenia besides exercise?

The basic nutritional supplementation to prevent muscle loss and promote muscle growth is adequate protein intake. The lower the daily protein intake, the higher the prevalence of sarcopenia. To prevent muscle loss, at least 1.2 to 1.4 grams of protein per kilogram of body weight per day is recommended, and for muscle growth, 1.6 grams per kilogram is advised. Since the amount of protein the body can use for muscle synthesis is limited, it is most important to consume an appropriate amount evenly across three meals rather than all at once.

For older adults who have weakened teeth and digestive abilities and find it burdensome to consume meat, black soybeans are recommended as a plant-based protein source. Black soybeans contain more than twice the protein content of beef and have higher intestinal absorption rates. Even if not black soybeans specifically, the protein difference among various types of beans is small, so consumption can be based on preference. Additionally, supplementing with protein powders or protein-rich beverages such as soy milk and yogurt is also beneficial.

This content was produced with the assistance of AI translation services.