Muscles and sarcopenia

Our body has about 640 muscles, which should maintain their strength and function as long as possible and contribute to a "moving" life. However, technical advances such as

the car or the elevator are increasingly turning us into movement mufflers. According to the principle "use it or lose it", a serious muscle loss occurs.

Muscle types

A distinction is made between

the smooth, involuntary musculature of the internal organs (e.g. in intestinal and vascular walls),
the striated, involuntary heart muscles and
the striated, voluntary skeletal muscles, which consist of two types of fibres, the red, small muscle fibres (type I) for endurance strength and the white, large muscle fibres (type II) for explosive strength.

The skeletal musculature

A skeletal muscle consists of many muscle fibres, which in turn are made up of muscle fibrils. A muscle fibril is made up of hundreds of sarcomeres connected in series. These are 2.5 µm in size and consist of the protein molecules actin and myosin. During muscle contraction, the myosin hooks into the actin and shortens the sarcomere by 1 µm.

The muscle contraction is coordinated in motor units. These consist of a nerve cell of the cerebral cortex and spinal cord (motoneuron), connecting nerve fibres (axons) and several muscle fibres. For fine motor skills, an axon innervates approx. 10 muscle fibres as opposed to up to 2000 muscle fibres for gross motor skills.

Muscle atrophy and sarcopenia

The condition of the skeletal muscles is subject to a control loop of its intensity of use. Thus, the strength athlete can train impressive muscle bundles, while the idle "couch potato" has lost large parts of his skeletal muscles. Muscles want to be moved. However, this is increasingly being counteracted by the lack of movement in civilisation and the handicaps of old age. Muscular inactivity first leads to muscular atrophy, later to sarcopenia:

Muscle atrophy sets in after only a few weeks. In atrophy, the sarcomeres are broken down, the muscle fibres are thinned out and muscle mass is reduced. It is fatal that the muscle atrophy is usually not noticeable externally because fatty tissue replaces the missing muscle volume.
Long-term muscle inactivity leads to sarcopenia. In addition to muscle atrophy, damage to the motor units occurs, resulting in disturbed nerve signal transmission. The thinned out skeletal muscles are then not only powerless but also misdirected. The typical patient with sarcopenia moves his voluminous body trunk in small steps on slender legs.

Nerval misinnervation leads to impaired reaction and coordination, which can result in falls. Sarcopenia also causes damage to other organ systems. Inactivity causes the bones to break down the basic osteoid substance, resulting in osteoporosis. Lack of exercise underchallenges the brain cells, which can lead to dementia. Furthermore, the muscle-replacing fatty tissue promotes diabetes mellitus. Similar to type II diabetes mellitus, sarcopenia seems to become a widespread disease. Well over half of all German citizens over 50 years of age already exhibit the symptoms of sarcopenia.

Everyday muscle exercises "in passing”

One should consciously and frequently move the muscles in everyday life. Here are some of our recommendations:

Do as much as possible on foot: Use the stairs instead of the elevator, go shopping instead of driving, carry things instead of pushing, etc.
Include small everyday exercises: Brushing your teeth in the ski squat, blow-drying your hair in the one-legged position, telephoning while standing etc.
Do moderate sports: Best 3 to 4 times a week for 20 to 30 minutes, alternating between strength exercises, stretching, back exercises and endurance training.
Pay attention to healthy nutrition: Align the calorie intake with the activity, food with little carbohydrates and fats, but rich in protein and vitamins with fruit and vegetables.

Recommended reading: Froböse I. Hidden diseases. How to stop them before they break out. Gräfe and Unzer, Munich 2008