Sarcopenia
The publishing house "Eksmo" presents the book by Valery Mikhailovich Novoselov "From neurons to hormones. Modern scientific knowledge about gerontology and tips on how to protect your body and brain from premature aging."
Aging is inevitable, but there are a number of processes that a person can influence in order to live healthy and active as long as possible. These include sleep patterns, homeostasis, hormones, metabolism, stress, nutrition and physical activity. Valery Novoselov, a geriatrician with 30 years of experience, a neurologist, in his new book tells what processes in the body change with age, how to take care of yourself properly to prevent problems in the future, and what to do if age-dependent diseases are already bothering.
We suggest reading a fragment of the book dedicated to sarcopenia.
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The world is paying more and more attention to the problem of sarcopenia. This term was proposed by I.Rosenberg in 1989, and the diagnostic concept of the syndrome was formed later, in 1998. In recent years, we have literally seen an explosion of interest in this topic, and it is even strange that this gigantic, rather than a private and small problem, has not been noticed for so long in our catastrophically aging world.
You often see such people: they are slowly, supporting each other, walking next to you on the street. Or in supermarkets, where they move, as if laying the upper part of their body on a cart for support and pushing it in front of them. It's just that you don't think of them exactly as patients, believing that this is normal. After all, they are part of our world.
So what is sarcopenia? This is a decrease in the volume and strength of skeletal muscles. The process itself is closely connected with age, with the processes of involution of our muscle tissue. It is manifested by a decrease in physical activity, muscle weakness, increased fatigue. It leads to a decrease and then loss of the ability to perform daily work, first intensive, then less intensive, and eventually to hypomobility. As it develops, it seriously reduces the quality of life of an elderly and old person.
Thus, sarcopenia is an atrophic degenerative change in skeletal musculature associated with age and leading to a gradual loss of muscle mass and its strength. Sarcopenia is a syndrome characterized by a progressive and generalized decrease in skeletal muscle mass, its strength and the risk of developing complications such as impaired mobility, decreased quality of life and death (EWGSOP, 2009).
People with this syndrome feel muscle weakness, a decrease in the speed of their movements, it is more difficult for them to perform fast movements that require muscle strength and endurance (running, long walking at a fast pace). At advanced stages, dependence on outside help is gradually increasing.
Sarcopenia is often associated with various pathological conditions, for example, with increased insulin resistance, dementia, falls, fractures, and eventually leads to a collapse of viability, hospitalization and death of the patient. Previously, sarcopenia was considered to be a decrease in lean mass by two standard deviations measured with two-energy X-ray absorptiometry in relation to a young healthy adult of the same sex. This approach had a number of advantages: it was understandable, and the diagnosis could be carried out during an osteoporosis examination.
In 2010, the concept of sarcopenia was revised. The European Association of Clinical Nutrition and Metabolism proposed to determine it with a decrease in muscle mass of more than two standard deviations, and, importantly, this must necessarily be combined with a decrease in a person's walking speed below 0.8 m/s.
The issues of classification of sarcopenia have not been definitively resolved, and many of them are controversial. However, we distinguish presarcopenia (or dinopenia) – a decrease in muscle strength without impaired movement function, and sarcopenia proper, when there is a decrease in muscle strength, and hypomobility occurs. The European Working Group on the study of sarcopenia in the elderly proposed to distinguish three stages of the syndrome: a decrease in muscle mass, a decrease in muscle mass and strength, and the third – a decrease in all parameters.
Accurate statistics on the representation of sarcopenia, even if someone says that it exists, does not exist for many reasons. These are different assessment methods, different approaches, and the lack of uniform criteria in different populations. For example, when they say that 22% of people have sarcopenia syndrome among the elderly aged 60-74 years, the question arises: is it possible to include such different age groups as 60 and over 70 in one focus group at all?
Let me remind you that the maximum muscle development in humans occurs at the age of about 25-30 years, by the age of 50, muscle mass decreases. In most cases, the average loss of muscle mass in a person is about 1% per year after the age of 35-40 years. After 50 years of age, muscle mass decreases by 1-2%, muscle strength – by 1.5–3% per year, in men this is more pronounced than in women.
At a young and middle age, under the influence of physical exertion, microtrauma is formed in the tissue of skeletal muscles. Stem cells migrate to the area of microtrauma, which become active and begin to produce a variety of myogenic factors, which leads to the fusion of existing muscle fibers and stem cells with the formation of a new, enlarged and stronger muscle fiber (hyperplasia). These processes are disrupted in old age.
As a standard of muscle strength, the definition of the strength of the quadriceps femoral muscle is used, which decreases at the age of 80 by 20-40% compared to persons of 25 years of age. The biceps muscle of the shoulder (the well–known biceps) weighs 174 grams at the age of 30, loses 20 grams by the age of 60, and another 35 grams by the age of 70.
The muscles in old age on the section look pale, dry and tight, as if stretched, their vascularization falls. It is important that we see these changes in the entire skeletal musculature. Pathophysiological changes in musculature are characterized by a total decrease in the number of muscle fibers, as well as pronounced infiltration of skeletal muscles by fibrous and adipose tissue. At the level of muscle fiber, degenerative atrophy of myocytes occurs, the number of neuromuscular units decreases, the number of muscle fibers of the second type decreases, which are fibers of rapid contraction and provide, first of all, rapid human actions (for example, running).
In the development of sarcopenia plays a role:
– systemic inflammation;
– circulation and tissue hypoxia;
– reduction of protein synthesis;
– alimentary factors: poor nutrition, gastrointestinal motility disorders;
– hormonal changes: age-related decrease in levels of STH (somatotropic hormone, growth hormone), testosterone, estrogen and insulin-like growth factor;
– reduction of the content of immunoglobulin A, G, anti-inflammatory cytokines;
– strengthening of oxidative processes;
– age-related decrease in the activity of the alpha motor neuron of the spinal cord;
– decrease in the ability of muscle tissue to regenerate;
– age-dependent pathology, which includes sarcopenia at all stages and levels of development (osteoporosis, type 2 diabetes, Alzheimer's disease, cardiovascular diseases), it seems to give an additional acceleration to the syndrome.
Prevention of sarcopenia syndrome
1. Adequate physical activity with mandatory strength exercises.
2. Increased protein intake in the absence of contraindications from the kidneys. The total protein intake should be 1.2 g / kg of weight / day, additional administration of protein in a dose of 0.25 g / kg / day to patients with sarcopenia causes a significant increase in "lean" weight.
3. The use of protein mixtures and amino acids (leucine, isoleucine, valine).
4. I will allocate four more substances: L-carnitine, carnosine, L-arginine, creatinine.
5. Therapy with testosterone preparations for men (if there are no contraindications).
6. Estrogen therapy (for women, there is almost no evidence).
7. Low-dose STH (this is an off-label appointment only, in addition, it is unclear whether it should be used if its indications are within the reference values), data on the benefits of this hormone are extremely contradictory.
8. Vitamin D3, polyunsaturated fatty acids.
9. Therapy of the main pathology of old age (type 2 diabetes, macroangiopathies, neurodegenerative and others).
The effectiveness of physical exertion exceeds the results of other types of sarcopenia treatment used without combination with physical exertion (various variants of hormone replacement therapy, nutrition correction). The ideal type of physical activity for the elderly is Scandinavian walking, which uses the technique of walking with sticks. Scandinavian walking has a number of advantages for older people, as it is simple in technique and has no age restrictions, and more than 90% of the muscles are involved in practicing it.
We can try to intervene in the chain "physical activity – moderate tissue hypoxia – activation of hypoxic factors – gene expression – adaptation" with the help of special interval hypoxic exercises, affecting the synthesis of hypoxia-induced factor (HIF), heterodimers that affect 2% of all human genes and trigger a cascade of complex adaptive biochemical reactions. In this case, we put a load on the mechanisms of biochemical and epigenetic adaptation, while the person is lying or sitting in a chair. But only the future will answer the question of how and to what extent hypoxic interval training can help us in the fight against sarcopenia.
Recently, a 90-year-old amateur runner Earl Fee ran 400 meters in 1:30.76 (the previous record was 1:46.78) and a distance of 800 meters in 3:42.50. We should expect a rain of records in the groups of veterans of older age groups in the near future.
Three characteristics of this syndrome are important in sarcopenia: it progresses, increases the likelihood of death and – most importantly for us – we can influence it.
It is easier to prevent sarcopenia than to fight it.
Maintaining the volume of skeletal muscles is one of the foundations of active and healthy longevity.
Exercise on a regular basis for as long as possible.
Power loads are a mandatory component of the fight against sarcopenia.
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