Lo purpose of the immune response is to inactivate o destroy the antigen, exploiting mechanisms immune of type cellular o humoral.
The immune response it begins to the comparsa dell 'antigens, following which quickly you activate i T e B lymphocytes, determining a response primary or a secondary.
Initially, our body DON'T è able to di reply efficiently a all the antigens but, after meeting them, odd a neutralizzarli giving rise to a primary response o aspecifica (the one that occurs after the first contact of the organism with an antigen) and after one secondary answer o specific (the one that the organism manifests following subsequent contacts with the same antigen) - a lot faster ed efficient of the primary.
The primary answer DON'T he's able to to prevent each infection but, once the first episode is over, it will be easier to defeat subsequent attacks the same pathogen. This is the principle which is at the basis dell 'immunization like prevention of the diseases.
During the phase intrauterine (until birth), immunity is passive type, as - crossing la placenta - antibodies of the mother they should protect the fetus from pathogens. After la birth real immune development begins, reacting all 'exposure to environmental agents; remember that they are two agents favoring a correct immune development Natural childbirth el 'breastfeeding. With aging decreases l'effectiveness of the immune system, resulting in a greater exposure bacterial infections e viral (13, 10).For further information: Natural Supplements to Strengthen Immune Defenses
Immune System and Sport
Most of the studies on effects dell 'physical exercise on immune system have been practiced evaluating some parameters before e after la physical performance. Not always i results were identical and, sometimes, frankly contradictory.
La ragione main of this inconsistency is to be found in the different condizioni experimental used and, in particular, in the diversity of the stimulus attributed (type of exercise, intensity, duration and density), as well as in diversity of sample analyzed - which, in some cases is represented by athletes conditioned, while in others by subjects sedentary.
In all studies, carried out both on trained athletes and not conditioned subjects, appeared, immediately after physical exertion, leukocytosis (5, 8).
Leukocytosis is natural biphasic since, to a immediate increase to the granulociti e lymphocytes circulating, they follow - after a few hours from the cessation of effort - lymphocytopenia e neutrofilia relative.
Most researchers agree that a increase more stand out to the lymphocytes a CD8 phenotype (O "suppressor"), respect to those a CD4 phenotype (O "helper"), perceivable by using the data as an absolute number rather than a percentage. This determines a reduction of relationship CD4 + / CD8 +, which represents a first segno di immune imbalance (13).
The cells also appear to be affected "natural killer", whose outdoor seems exalted during lo sforzo physical, with increase of the CD16 + cell. It is assumed that the outdoor of NK cells reaches the maximum immediately after exercise, yes reduce after two hours e DON'T yes still normalized after 20 hours (3, 4).
A research carried out on a group of amateur sportsmen practitioners marathon ed ultramarathon states that in all the athletes examined the number of cells NK results top compared to the control group, with significantly higher values than the norm (2). It was then documented, after physical activity, a reduced adherence macrophage it's a decreased phagocytosis, with modifications proportional to the intensity performance.
Some Authors support even that the outdoor Sports protracted long depressed l'immunità aspecifica, making so those who have practiced sports for a long time, as those who have been competitive for years, more susceptible infections. The rest in many athletes prominent, even the level of immunoglobulin-G circulating seems to be lower to the end area of competitive season compared to the beginning (13), as shown in the table below.
Variation in the concentration of immunoglobulins in athletes (from Immunologia e Sport Società Stampa Sportiva, Rome, 1990).
It is therefore evident that the phase where the immune system is more vulnerable is that immediately next one to the physical performance; during physical exertion on the other hand, is liberated one great amount di hormones e mediators, so it is not easy to trace the mechanisms with which they interact.
In summary, at present it can only be said that one "psychophysical stress excessive is able to favor a situation of immunodeficiency, clinically documentable with shapes infectious, sometimes trivial, talaltra gravi.
Lo stress can therefore be defined as a series of events, including defined stimuli "stressor", which come perceived from the organism e to which it follows a series of physiological reactions, which have the task of producing a response to the stressor.
On the other hand, for most people, the term stress takes negative connotations, though some they result "stimulated" positively. La response physiological in fact, stress takes the form of release of some neurotransmitters e hormones of adaptation.
However, stress also needs to be contextualized and measured. An important distinctive feature of this factor is his duration; is defined acute the event that lasts few minutes o a few hours, while it defines itself chronic what persists for days, settimane o months. In the next article we will go into more detail.
To better understand the correlations between exercise stress and susceptibility to infections, read on on the following page:Infections in Sports
or go back to the previous article:Physical Exercise and Immune System
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- Amato S., Francavilla C., Francavilla G. Tolomeo M., Tripoli S., Modifications of some immune parameters in a group of amateur athletes practicing marathon and ultramarathon. Sports Medicine 2005, 58: 203-206.
- Ambrogi F., Ferretti A., Sbrana S., Ferretti GP, Tessarolo A. Effects of intense physical exercise on lymphocytic apoptosis in trained subjects, 1997 Sport Medcine 50: 389-392.
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