We now have more data on why physical exercise prolongs life, rejuvenates the body and leaves us better protected against many diseases.
From the moment we are born, a process of replacing cells that have finished their useful life begins, by producing new ones from stem cells, which, of course, have to be recycled, but with age this capacity is lost and many remain as senescent cells, which emit pro-inflammatory cytokines and collagen and connective tissue growth factors, resulting in wrinkles and aches and pains.
A specialised progenitor type of these cells has been identified in the bone marrow and shown to support the generation of immune cells called lymphocytes in response to physical exercise. Lymphocytes generate a massive attack against viruses and bacteria. There are several classes and one of them is called natural killers.
Many types of stem cells, including immune cell progenitors, co-exist side by side in this immature state, ready to evolve into adult cells. These are the ones that give rise to bone, skeletal tissue, fat cells and the haematopoietic progenitors that will eventually evolve into the cells of the immune system.
These stem cells reside in places other than the bone marrow, around blood vessels and arterioles, which, upon impact, stimulation, pressure from moving muscles and joints during exercise, will promote and stimulate the development of a cascade of growth-stimulating signals.
They have discovered a previously unknown pathway by which exercise, detected through mechanosensitive protein Piezo1 in the membranes, triggers the production of a developmental factor in these cells, which in addition to producing bone also produces cells of the immune system.
It was known that exercise can boost the immune system, but the breakthrough work by Zen and colleagues provides the reason why this happens and why daily exercise extends life and prevents dependence and early physical frailty.
Thus, exercise, detected through the mechano-sensitive protein Piezo1 in the membrane of these cells, triggers the development of the immune system to stimulate the production of a signal that promotes the maturation of their embryonic cells.
The movement sensing mechanism is well established to play a role in bone physiology, but stimulation is also necessary for lymphocyte precursors. Osteogenesis (formation of bone producers) and lymphopoiesis (formation of lymphocytes) in the bone marrow are maintained by mechanical stimulation.
Mechanosensing has been described for other cell types, for example, pancreatic progenitor cells, intestinal stem cells and endothelial cells lining blood vessels. It is possible, then, that mechanosensing, which acts every time we exercise on the cells lining our arterioles, contributes to the maintenance of other types of stem and progenitor cells in the rest of the body and maintains the health of all tissues.
In this way, exercise, let's say swimming, by moving so many muscles, activates those receptors that are triggered by the pressure and result in a cascade of general renewal and rejuvenation and defence against all kinds of diseases.
We are made to be on the move, for the reasons we have mentioned. I don't agree with the advice of half an hour three times a week, I don't think it is based on any solid argument. According to this paper, the more movement the better, but on a daily basis.
We have known for some time through large observational studies that exercise can reduce the risk of all-cause and disease-specific mortality.
A team of cardiologists from the Cardiovascular Institute of the Hospital Clínico San Carlos have studied patients hospitalised for covid-19 to conclude that regular physical activity increases the chances of survival in these patients by up to eight times over those who lead a sedentary life.
They were conclusive: the group that had maintained a constant, light or moderate physical activity had a mortality risk of 1.8% compared to 13.8% for the group with a sedentary lifestyle; in other words, people who exercise regularly are up to eight times more likely to survive than those who are sedentary. Provided we include the Mediterranean diet.
"Regular physical exercise is an essential factor as it reduces eight times the chance of dying from covid-19 when the person needs to be admitted to hospital," says Julián Pérez-Villacastín, director of the Cardiovascular Institute of the Hospital Clínico San Carlos, who carried out this research, surrounded by a group of collaborators. Research that has been published in the American Scientific Journal of Infectious Diseases, Infectious Diseases and Therapy.
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José Antonio Rodríguez Piedrabuena
Specialist in psychiatry, management training, group and couple therapies.