June
21, 2021
7 min read
This story originally appeared on The Conversation
By Carlos Ayán Pérez , University of Vigo
Some time ago, when the lines at the supermarket were made without social distance (or any discretion), I heard a mother of two children comment something to the patient cashier. The point: although it had been more than six months since he had turned 50, he was in good health.
Apparently, he did not seem to perceive the passage of time very strongly. Until that morning. It was then that he realized that all the years had fallen on him.
This woman related that one of her children had forgotten something at home just when they were on their way to school. Realizing it, they had to rush back for it.
Between surprised and resigned, the mother narrated how, when she wanted to run, her muscles committed the impudence of not obeying her. This time, she had been unable to reach the desired cruising speed. The same one that on so many other occasions had allowed him to be punctual when time was running against him.
Such a “lowering of the arms” of his locomotor system forced him to rethink the long-remembered slogan “Not years weigh, but kilos. But not. She perceived that what weighed, in effect, was not the years: it was the physical inactivity.
One of the great scholars of sports training, Kazimierz Fidelius, established a classical biomechanical model. In it, the human being was conceived as a “biomachine” made up of three large systems .
First, the direction, represented mainly by the brain. Second, the power system, made up of all the organs involved in the energy transformation processes. Finally, the so-called motor system, the locomotor system.
According to Fidelius, the movement would be responsible for improving and providing feedback. Thus, an improvement in physical condition and, therefore, health would be achieved.
Modernity makes movement more dispensable
When the advances of “modern man” are used to supply the locomotor system, the need to generate movement to move is eliminated.
This strategy is becoming increasingly fashionable. Not only through the use of motor vehicles, but also with the proliferation of devices such as electric scooters. Its use among the younger population should be discouraged because it invites physical inactivity from an early age.
The risk of suffering from what are known as hypokinetic diseases is also increased. They are those in whose appearance physical inactivity plays a fundamental role. This is the case, among others, of obesity, hypertension or type II diabetes.
These pathologies, which are part of the letter of introduction to entering the elderly, today make their debut much earlier than expected. They give rise to the concept of acquired aging, in which the lack of physical activity plays a leading role.
It was in the middle of the last century when Jeremy Noah Morris , a doctor, raised the first hypotheses related to the effects of physical activity on health. The researcher found that the collectors of the double-decker buses had up to a 30% reduction in the risk of cardiovascular disease compared to drivers. The reason: going up and down stairs.
From this moment on, numerous studies have been confirming the benefits of physical activity in the main organs and systems of our body.
How physical activity affects our body
Thus, with regard to the nervous system, scientific evidence indicates that people who have led an active life have a lower risk of suffering from dementia . Similarly, longitudinal studies indicate that the chances of suffering from cancer seem to be attenuated by an active lifestyle.
At the cardiovascular level, it contributes to the heart being less fatigued . Thanks to physical activity, this organ pumps more blood with each heartbeat. Therefore, it needs to beat fewer times per minute to provide oxygen to the entire body.
If the activity is also of a certain intensity, it increases the capacity of the lungs to absorb and transport oxygen , delaying the onset of fatigue.
Muscle fibers, meanwhile, improve their vascularity . This favors the uptake of glucose, reducing its concentration in circulation. In other words, there is greater control of the so-called “blood sugar level”.
There are other adaptations generated thanks to physical activity. For example, greater absorption of calcium by the bones, which reduces the risk of developing osteoporosis.
Also the mobilization and subsequent oxidation of adipose tissue (fat) to convert it into energy. It is a process that helps control body weight.
In addition, it increases the elasticity of the arteries, helping to reduce hypertension, and increases the release of endogenous opiates (such as endorphin), which promote the feeling of well-being.
However, little is known about what happens when people who are active stop being active.
Loss of activity
There are studies that have confirmed the reversibility of the benefits of physical activity in the absence of it. Among others, bone and muscle mass are lost, weight is gained or cardiorespiratory capacity deteriorates.
However, the vast majority of these investigations are carried out in people who have been subjected to periods of immobilization (bedridden patients), astronauts or elite athletes. Therefore, the results are not transferable to the general population.
To be able to more or less clearly identify what happens when a person who has been active stops being so, it is necessary to design a longitudinal cohort study. Follow up a population group for a specified period.
It should collect information on the level of physical activity that a person performs, but also on many other variables related to their lifestyle and health. This is the case of nutrition, sleep or work habits, as well as the control of the different pathologies of the participants during the study.
Obtaining data on the amount of physical activity carried out is a complicated task. In general, questionnaires are used that not everyone knows how to answer correctly. Furthermore, they are subject to significant estimation errors.
The solution is through the use of accelerometers, which monitor the amount of physical activity carried out objectively.
However, in order to determine the level of activity or its decrease, the participants would have to wear the tool throughout the study. At a minimum, during previously established intervals.
The subsequent statistical analysis would also be complex. After all, factors that could indirectly influence health status should be isolated. And not only that, but also the physical activity to be carried out. 
This article is republished from The Conversation under a Creative Commons license. Read the original article .