Portugal is a country with a high average life expectancy, around 82.5 years according to Eurostat data from 2023, but healthy life expectancy is only 59.6 years, meaning that Portuguese people may spend over 20 years with limitations and reduced quality of life. This situation is frequently associated with aging, but a often underestimated factor is the condition of the muscles.
Muscles are not only important for physical appearance, but also for autonomy in old age and for essential metabolic functions. After meals, blood glucose is stored in the muscles as glycogen. With less muscle, sugar remains in the blood longer, the pancreas releases more and more insulin, and over time this mechanism begins to fail. With age, muscle mass begins to decrease after the twenties and, after seventy, approximately one percent of mass and three to four percent of strength are lost per year. When this loss becomes pronounced, it is called sarcopenia, associated with more falls, fractures, loss of autonomy, and higher mortality. Since 2019, European doctors have defined it by strength rather than muscle volume, because strength decreases two to five times faster.
An extreme example of the importance of muscles for the organism is what happens in space: even healthy and fit astronauts lose ten percent of their back muscle volume in just eight days without gravity, which is why they do two daily hours of mandatory exercise. The body does not preserve muscles and bones simply because it created them, but rather in response to their use.
The good news is that the body's adaptability changes with age, but does not disappear. A study published in 1994 in The New England Journal of Medicine with one hundred nursing home residents, with a mean age of 87 years, showed that ten weeks of strength training increased strength by 113 percent, compared to only three percent in those who did not train. A simple test to assess strength at home consists of standing up and sitting down five times in a row without using hands; if it takes longer than fifteen seconds, leg strength is below normal. The World Health Organization recommends exercising all major muscle groups at least twice a week and, after age 65, adding strength and balance activities at least three times a week. Although it is not possible to control aging, it is possible to influence and improve functional status at any age.
