Physical inactivity and sedentary lifestyle – What effects on health?

What are the health risks of physical inactivity and a sedentary lifestyle? 

Muscle exercise physiologists have long focused on the risks of physical inactivity . It has been proven since the 1950s that not moving enough is harmful to health and the first WHO recommendations were limited to physical inactivity. Then, gradually, in the years 2000 to 2010, the harmful effects of a sedentary lifestyle independent of those of physical inactivity were demonstrated. We can thus be active-sedentary or inactive-sedentary, which is the lifestyle with the highest risk. To compensate for the harmful effects of a daily sedentary lifestyle of 8 to 10 hours per day, we must do between 1.5 and 2 hours of physical activity each day. It has been clearly shown that the most sedentary people at work are also sedentary on weekends and during vacations. This is what I call “chair addiction”.

While the population has quite well understood that “sport” is good for health, it has not understood that not doing physical activity (PA) and/or being too sedentary is dangerous for health . Moreover, many professionals in the medical and paramedical world are still not convinced of this. For example, all these professionals ask their patients the question “  Do you smoke?  ”, but practically none of them ask them “  Do you move?  ”, “  How much time do you spend sitting during the day on average?  ”.

Another essential factor, inseparable from physical inactivity and sedentary lifestyle, is physical capacity . Physical capacity, which is the most powerful validated marker of life expectancy, particularly in good health, is very little known by practitioners. It represents the health capital of the subject. This is regardless of age, sex and health status. For example, a 50-year-old man who has had prostate cancer and a heart attack and who is able to climb four flights of stairs without being out of breath will live on average longer than a 50-year-old man who has never been ill, only able to climb two. However, PA is the only direct way to increase one’s level of physical capacity , regardless of sex, age and possible pathologies. Our medications do not directly increase physical capacity, they improve symptoms, which allows one to be more active. In other words, a patient treated medically in an optimal manner who does not move will not increase his physical capacity. In prevention, eating well, sleeping well, not smoking, limiting alcohol consumption… are essential, but the only way to improve one’s physical capacity, therefore one’s health capital, as defined by the WHO, is to move more.

Also Read: Six Scientifically Proven Benefits of Yoga

The effects of outbreaks on the population have confirmed the importance of activity and physical capacity. Studies conducted in Western populations have clearly shown that, in the event of infection by the virus, the most fragile patients were not simply those who had comorbidities, but those who were the most inactive and/or with the lowest physical capacity. Hence the more appropriate term of syndemic, effects of the environment and lifestyle on the consequences of a disease on the population, preferred by several epidemiologists to that of pandemic. The effects of outbreaks have therefore clearly shown that these populations were not in good health.

What are the benefits of physical activity in terms of prevention?

•   In primordial and primary prevention, daily moderate PA reduces the risk of developing a chronic disease by an average of 30%.This has been proven for at least 35 chronic diseases. Of course, this is an absolute risk. Individual risk varies depending on other modifiable or non-modifiable risk factors.

Since 2011, AP has been a non-drug therapy validated by the High Authority for Health (HAS).

•   In secondary and tertiary prevention, PA reduces comorbidities, complications of chronic disease and can limit its progression.After a well-managed and optimally medically treated acute coronary syndrome and when regular moderate PA is maintained after the event, a decrease of approximately 40% in overall mortality, 30% in cardiac mortality and 25% in the risk of recurrence is reported. Many cancer patients who are well-managed surgically and medically emphasize the beneficial effects of adapted PA (APA) on their quality of life and in particular on improving the feeling of fatigue. PA remains the only treatment for fatigue induced by anticancer treatments. PA always improves the quality of life of the chronically ill. This is essential, because until one has been ill, the weight of the burden in everyday life that a chronic disease represents is underestimated by caregivers and sometimes by the patient’s entourage.

Let us recall that APA for therapeutic purposes is part of the treatment of any stable chronic disease and that its non-prescription is a loss of opportunity for the patient. Training courses (DPC) are offered to learn how to prescribe APA and information is available on the HAS website.

How can we explain the harmful health effects of physical inactivity and a sedentary lifestyle?

The variety of pathologies favored by the choice of a sedentary and/or physically inactive lifestyle has long been unexplained. The decrease in the practice of one’s daily PA while maintaining one’s usual diet is quickly accompanied by an accumulation of fat, in particular intra-abdominal, the harmfulness of which is well proven. A sedentary lifestyle also favors the accumulation of this intra-abdominal fat , on the one hand due to the lack of activity, and, on the other hand, because it is often accompanied by snacking . Indeed, the less we move, the more we eat!

We now know that all organs communicate with each other via the cytokines they release into the circulation, which bind to specific membrane receptors located on the cells of other organs. Intra-abdominal fat, which is metabolically very active, releases adipokines, which increase levels of inflammation and oxidative stress and reduce the effectiveness of the immune system. These chronic changes are the basis for most chronic diseases, including cancers that are more common in overweight or obese people. But this low-grade chronic inflammation is also observed in sedentary and/or inactive people who are not overweight. Dosages in these people, particularly of CRP, the most sensitive marker of inflammation, confirm this.

And, conversely, how can we explain the beneficial effects of physical activity?

The polypill effect of AP has long disturbed the medical mind, because it is considered inexplicable by many. To understand these effects, we must go back to our ancestor Homo sapiens who, during his evolution, had to, in order to survive, favor two parts of his genome. A genome that remains very close to ours. On the one hand, the genes that facilitate the storage of fat , because our ancestor did not eat his fill every day. Today, we stimulate these genes far too much, hence the obesity epidemic that overwhelms us. On the other hand, the endurance genes , because, at the time, he practiced hunting by exhaustion. We no longer stimulate these genes. However, muscle contraction, by stimulating these genes, promotes the release of myokines which, by diffusing in the body, reduce inflammation, oxidative stress and stimulate immunity and vasomotion. Other cytokines, grouped under the term exerkines, released by most organs (heart, liver, bones, etc.) have recently been isolated. Thus, we are genetically programmed to move and, to preserve our health capital for as long as possible, we have no other way out than movement .