UNDERSTANDING MUSCLE

Muscle physiology

The human body contains 600 muscles. As essential energy reserves, muscles do not only play a key role in motor, respiratory and cardiac function: they also interact with many organs and biological mechanisms, and are essential to good overall health.

The benefits of muscle activity

Muscle exercise benefits health throughout life: a reduced risk of stroke and osteoporosis, prevention of hypertension, slower progression of Parkinson’s and Alzheimer’s disease, improved digestion, less stress, increased fertility and better mood, among other effects!

Indeed, during muscle exercise, muscle secretes small molecules called myokines and releases them into the body, where they have beneficial effects on the whole body. In particular, they help to burn more fat mass and to increase our sensitivity to insulin, thereby reducing the risk of developing diabetes

Muscle during ageing

Physiologically, our muscles waste away with age. From the age of 20, we lose 4% of our muscle mass every 10 years. And from the age of 70, muscle accounts for only 25% of our total body weight! Muscle therefore has to be preserved and trained throughout life. 

In older people, tackling muscle loss means preventing loss of independence and the onset of serious and very common diseases such as osteoporosis.

Or sarcopenia, the progressive, generalised loss of mass, strength and quality across all the muscles. This process begins as early as the age of 50 and can lead to a loss of more than 30% of initial muscle mass. Its consequences are many, in particular an increased risk of falls, the leading cause of injury-related death in people over 65.

Muscle is affected in many common chronic diseases  

When muscle  works poorly or weakens, the consequences can be severe or even irreversible. In many diseases, there is a loss of muscle mass and strength that impairs patients’ quality of life.

For example:

  • Six months after a stroke, whatever its severity, a loss of muscle mass of nearly 4% is observed in the lower limb and of 8% in the upper limb.
  • Similarly, in cancer, the tumour and the intensive treatments make patients’ muscles more fragile and weaker. Yet good muscle health is now known to be an extremely important factor in prognosis and in response to treatment.
  • Heart failure also causes particularly marked muscle deconditioning. Throughout life, muscle has to be preserved and trained to maintain a good quality of life and to help prevent serious and very common diseases.

See also our video series The amazing secrets of muscle