Losing muscle mass as you age is inevitable. We speak of sarcopenia when muscle wasting is accompanied by a consequent loss of strength and physical performance is significantly degraded. A major cause of loss of quality of life and autonomy, this syndrome also affects the general state of health of the elderly. Maintaining physical activity and taking nutritional measures help fight it.

Definition

Sarcopenia is an aging syndrome, corresponding to a progressive and generalized loss of muscle mass, strength and function.

The state of presarcopenia is characterized only by the decline in muscle mass, mainly due to the loss of muscle fibers associated with age. The efficiency of the contraction of the remaining fibers is preserved.

In addition, sarcopenia is associated with loss of muscle function. Muscle fibers atrophy and their resistance strength is affected, as is physical performance (that is, the ability to perform motor tasks of everyday life).

When the functional loss is significant, doctors speak of severe sarcopenia 

Causes

The origin of sarcopenia is multifactorial. It is linked to a state of undernutrition, with insufficient protein intake, and a lack of physical activity (sedentary lifestyle), but also involves changes in the body related to aging or chronic disease, such as alterations protein metabolism and energy metabolism, hormonal changes, inflammatory and neurodegenerative processes … 

Diagnostic

Clinical tests

Specialists assess the degree of sarcopenia using simple tests that measure physical performance. The diagnosis is made when:

•  The walking speed is less than 1 m / s over 6 meters or 0,8 m / s over 4 meters.
• The SPPB overall performance score (short physical performance battery), calculated from three tests scored out of four points, is less than 8. These tests assess the patient’s balance, walking speed and ability to rise from a chair five times in a row.
• The ability to perform a series of simple maneuvers, assessed using the TUG test (Time up and go test) – get up from a chair with an armrest, walk three meters to a landmark, turn around and come back to sit – are reduced.

Grip or extension and flexion tests of the knees are also performed.

Muscle mass assessment

Visible to the naked eye, muscle wasting can be objectified by measuring the circumference of the muscles of the limbs.

A simple and inexpensive method, bio-impedancemetry provides an indication of the composition of the body in terms of fat mass and muscle mass as a function of the resistance of the tissues to the passage of a low intensity current.

Medical imaging (scanner, DEXA or MRI scanner) is more precise, but little used in current practice.

The people concerned

From the age of 30, muscle mass decreases by approximately 1% per year. This process accelerates from the age of 50.

It is estimated that around 10 to 30% of people in their sixties are affected by sarcopenia, the figures varying according to the criteria used and the populations studied. This rate rises to 30 to 50% among those over 80.

Risk factors

The risk of sarcopenia is increased in sedentary and undernourished people.

The risk of undernutrition stems in part from the decrease in appetite and food intake observed in seniors. It can be increased by many pathological situations:

• cancers,
• renal or digestive pathologies,
• poor oral health, 
• psychiatric and neurological disorders,
• acute conditions (infections) and hospitalizations
• drug treatments,
• various pathologies imposing a restrictive diet …

Elderly people who are isolated, dependent or in a situation of poverty tend to eat less and be less active.

Decreased physical performance

Sarcopenia causes loss of motor skills. As it settles down, we become less enduring and more tiring. The actions of everyday life – walking, getting up from a chair, climbing stairs… – are becoming more and more difficult, which leads to a loss of autonomy and quality of life. The balance is compromised and the risk of falling increases.

Vulnerability to disease and morbidity

Decreasing physical activity increases the risk of osteoporosis, and therefore of fractures.

The decrease in defense against infections and healing difficulties are explained by a decrease in the body’s ability to rapidly synthesize protein compounds, in connection with the reduction in muscle protein mass, which constitutes a reserve of their components. (amino acids).

At an advanced stage, sarcopenia can lead to respiratory and digestive disorders linked to weakness of the intercostal muscles, diaphragm and intestinal wall.

The therapeutic strategy is defined by a doctor specializing in geriatrics or physical medicine and rehabilitation. It is based on an adapted physiotherapy program, combined with nutritional support.

Physical exercise

The exercise program mainly consists of strength-versus-resistance exercise of low intensity, allowing for muscle building.

• standing flexion / extension,
• lateral leg elevation,
• chair lift,
• raised knees,
• in a seated position, maintaining one leg raised parallel to the ground in contraction (isometric exercise of the quadriceps),
• etc.

Repeated sessions two to three times a week, for twelve to eighteen weeks, lead to improvement in muscle strength and power, even in very old subjects. Functional advances extend to walking speed, ease of getting up and reducing the risk of falling. 

Nutritional strategy

The main objective is to allow an optimal protein intake to stimulate protein synthesis and promote the production of lean muscle mass.

Increasing the protein intake from the diet is not always enough to reach the recommended daily allowances, estimated at 1 to 1,2 grams per kilogram of body mass per day in the elderly. Research shows that it may be relevant to supplement amino acids (leucine, citrulline), but also to introduce what specialists call pulsed nutrition, which concentrates 80% of daily protein intake in a single meal.

Fast proteins, so called because their absorption into the blood is very rapid during digestion, also have an interest in increasing the availability of amino acids for protein synthesis. This is the case, for example, with whey proteins (whey).

Vitamin D is of interest in preventing the number of falls.

Therapeutic education

One of the major challenges of management is to get patients to regain confidence in their abilities and agree to comply with this program over time. 

The prevention of sarcopenia is based on the same pillars as treatment, namely physical activity and nutrition.

Physical activity

Physical activity ideally combines muscle building exercises with endurance activities. Flexibility and balance exercises are also beneficial. For example, studies have shown the benefits of practicing Tai Chi.

For those who are not followers of sports activities, many daily activities – walking, gardening, shopping… – help to preserve our “muscle capital”.

Physical exercise also helps stimulate appetite and metabolism.

Food

The diet must allow a sufficient intake of protein. It must also be balanced and allow in particular essential contributions in fruits and vegetables (rich in anti-oxidants), or omega-3, so as to protect the organism from the harmful effects of aging.

The intake of food supplements with anti-oxidant, anti-inflammatory properties, or even active on the metabolism is possible (anthyocans, omega-3, ursolic acid…) but cannot replace a balanced diet.