This time, I'd like to talk about exercise and immunity.
Do you exercise to improve your immune system?
I don't know what kind of impression you have, but do some people have the impression that if you move your body, you will get warmer, and warmth = working immune system?
Various health people have theories about such stories, but most people are likely to believe them if they are recommended by people who claim to be experts in high-profile media.
It is up to the individual to decide what to believe, but there is a lot of uncertainty about exercise and immunity, which is discussed in the editorial presented here.
Contents
Exercise is called an antigen because it has been identified as a behavioral factor that can improve immune function and serve as a form of vaccination against certain diseases and infections. (Jee, 2019)
The authors of this study called it an "exercise antigen".
Exercise antigens have a protective effect on the human body when supplied in adequate amounts.However, the appropriate amount of exercise has not yet been established, and various researchers are divided in their opinions.
Numerous studies have been conducted to investigate the relationship between exercise and the body's immune response, and exercise has been identified as a behavioral factor that can enhance immune function in several settings.
Thus, it may serve as an adjuvant to the immune response.
Exercise-induced changes in immune function can be observed between acute and chronic exercise training.
The term "acute exercise" refers to a single bout of exercise, while "chronic exercise" refers to prolonged duration and frequency of exercise.
Many studies have reported sudden and temporary changes in the immune system after a single exercise session, which disappear shortly thereafter.
On the other hand, exercise performed consistently over a long period of time can result in positive or negative adaptations to the immune system.
These responses and changes are dependent on the intensity and duration of both acute and chronic exercise.If the exercise intensity is too weak or of too short a duration, acting as an exercise antigen will be ineffective.
Conversely, if the intensity is too high or the duration too long, it can act as a toxin, causing cell damage and destruction.
The immune system's response to acute exercise
Acute exercise is known to have many short-term effects on immune function, but there appears to be a contrasting effect between moderate exercise attacks and prolonged/intense exercise attacks.
At the onset of exercise, homeostasis is disrupted and a variety of neuroendocrine, metabolite, and immune responses are induced in proportion to exercise intensity and duration.
It is well known in academic circles that the constant changes in white blood cells, T cells, B cells, natural killer cells, immunoglobulins, and cytokines during and after exercise can have profound effects on the body's resistance to disease.
It has been stated that exercise induction of an inflammatory environment in muscle, especially in the case of muscle damage exercise, may result in increased lymphocyte homing to the site of vaccine administration and/or enhanced antigen uptake and processing.
They reported that the initial phase of the immune response is more efficient and that exercise has been shown to preferentially mobilize leukocytes with tissue homing potential that contribute to the inflammatory-induced environment.
Acute exercise-induced leukocytosis is triggered by neuroendocrine substances that increase the circulation of monocytes and dendritic cells.
These are potential antigens that increase the likelihood of migration to the site of antigen exposure.Finally, lymphatic drainage is known to be elevated by muscle contraction; therefore, exercise may enhance immune cell transport from the site of antigen administration to lymph node drainage.
Vaccination response can be measured and quantified in two main ways.
The production of antibodies by plasmacytoid cells and the response of memory lymphocytes stimulated by antigens.
Jee YS. How much exercise do we need to improve our immune system?: a second series of scientific evidence. J Exerc Rehabil. 2020;16(2):113-114. Published Published: 2020 Apr 28. doi:10.12965/jer.2040178.089
Exercise and the Endocrine System
When exercise is initiated, sympathetic nerve fibers are stimulated in the brain, cardiac output increases, and catecholamines are released from the adrenal medulla.
The brain activates the neuroendocrine system to produce adrenocorticotropic hormone from the hypothalamic-pituitary-adrenal axis, and the adrenal cortex releases cortisol.With increased cardiac output, cortisol and catecholamines are transferred to cells with a modified effector phenotype.
Effectors, along with other immune mediators (heat shock proteins, chemokines, and cytokines) remove trace substances and cytokine expression that affect organs as they travel to tissues.
Physical activity affects human immunity, but the extent of the effect depends on whether it is acute or chronic.Acute exercise is defined as a single exercise session, while chronic exercise is characterized by very demanding training routines that may involve strenuous exercise on a daily basis.
Factors affecting immune response and adaptation are being investigated to better understand the revealing effects of vaccine types from acute and chronic exercise.
This requires an understanding of the complex process of the immune system's response to vaccination before the possibility of exercise altering the response can be investigated.
Basic knowledge of immunity
There are three types of immunity in humans: innate, adaptive, and passive.
Since passive immunity is temporary and comes from other sources, this editorial will focus only on innate and acquired immunity.
Innate immunity is what people are born with and provides general protection.
It first detects invaders such as toxins, bacteria, and viruses, and then activates cells to attack and destroy them.Adaptive immunity involving lymphocytes develops over time through exposure to a variety of diseases, including immunity from vaccination.
Immunological memory is created after the initial response to a particular pathogen.
This allows adaptive immunity to respond more effectively when the same pathogen is encountered in the future.
Vaccination follows the same process of acquiring immunity.
The innate immune system is composed of white blood cells that exhibit non-specific responses.The adaptive immune system consists of T cells, B cells, and antigens with specific responses.
Natural killer (NK) cells are lymphocytes that are part of the innate immune system.
Instead of attacking pathogens directly, they destroy infected host cells, such as virus-infected cells and tumor cells.
Exercise and immune function
Exercise is an activity that improves physical fitness, health, and well-being through physical activity.
Development of motor skills, weight loss, increased muscle strength, improved cardiovascular system, and enjoyment are reasons to exercise.
Regular exercise strengthens the immune system and helps prevent a variety of diseases.Temporary suppression of the immune system can result from prolonged strenuous exercise.
Decreased phagocytic function of neutrophils and decreased numbers of lymphocytes and NK cells may occur 2 to 24 hours after prolonged strenuous exercise, impairing immune function and increasing susceptibility to infection.
On the other hand, the acute stress-induced immune enhancement hypothesis states that moderate exercise can improve the immune response.
Research studies involving the effects of chronic exercise on the body's response to vaccination have consistently shown that older adults who exercise moderately have improved immune function.
Studies in younger adults are relatively limited, with only one study providing evidence that increased exercise leads to improved response to vaccination.
The above research study reinforces the hypothesis that a single bout of moderate intensity exercise can enhance the immune response to vaccination.
In summary, acute exercise may enhance T-cell activity, while chronic exercise may lead to a decrease in T-cell activity.
However, both acute and chronic exercise increased the number of B cells.
Jee YS. Influences of acute and/or chronic exercise on human immunity: third series of scientific evidence. J Exerc Rehabil. 2020;16(3):205-206. Published 2020 Jun 30. doi:10.12965/jer.2040414.207
About Exercise
Regular exercise for 30 minutes a day, three days a week, for at least six months is necessary to obtain the beneficial effects of exercise.
Regular exercise strengthens the body's organs, thereby providing protection from disease or assisting in the recovery process.More specifically, regular exercise plays an important role in protecting the body from external antigens by boosting the immune system.
The immune system, the body's defense against disease, allows the body to develop so that it can recover from infections.
This can be seen when an athlete infected with coronavirus returns to the game or competition due to the production of antibodies.
About the immune system
The immune system recognizes foreign substances that enter the body as antigens, and the body's defense system is to produce antibodies to fight them.
Many studies have been reported on white blood cells, including subtypes of innate immune cells and NK cells, which are related to exercise.
These changes in immune cells due to exercise have been studied in the following ways.The effects of exercise as it relates to innate immune cell function have been
The innate immune cells of trained athletes and sedentary people were compared.
The results show that athletes have higher immune function than non-physically active people.
As a second hypothesis, they were investigating changes in immune cell function in subjects who train for a specific period of time at various intensities and durations under specific conditions.
It is known that the exercise group has a higher number of white blood cells (leukocytes, neutrophils, and lymphocytes) and NK cells than the control group.
It is also known that the number of white blood cells and NK cells increases after moderate exercise and after increasing maximal exercise.
Furthermore, as the intensity of exercise gradually increases and reaches its maximum level, white blood cells, neutrophils, lymphocytes, T cells, B cells, and NK cells increase and the T4 / T8 ratio decreases.
This may explain why there is a very significant increase in these cells after moderate or maximal exercise.
Thus, the increased number and function of NK cells during exercise is thought to provide an additional protective capacity and compensate for the immune vulnerability caused by the temporary decrease in the T4 / T8 ratio.
NK cells are part of the innate immune system that express spontaneous cytolytic activity against various tumors and virus-infected cells.
Unlike T-lymphocytes, NK cells do not require the involvement of antibodies or major histological synthetic antigens for initial virulence and respond rapidly to foreign substances.
Once the antigen-specific immune system begins to respond, it is controlled by NK cells, which account for about 15% of lymphocytes and are thought to play an important role in the first line of defense against the spread of malignant diseases.
Therefore, it is important to elucidate the effects of exercise on the number and activity of NK cells.In particular, we need to pay more attention to the role of exercise and how it strengthens the innate immune system.
Therefore, it is important to elucidate the effects of exercise on the number and activity of NK cells.In particular, we need to pay more attention to the role of exercise and how it can strengthen our innate immune system.
The question is, how much exercise is needed to improve our innate immunity and thereby improve our defense against viral infections?
Jee YS. Physical exercise for strengthening innate immunity during COVID-19 pandemic: 4th series of scientific evidence. J Exerc Rehabil. 2020;16(5). 383-384: Published 2020 Oct 27. doi:10.12965/jer.2040712.356
Summary
This editorial explained the relationship between exercise and immunity, and even explained the response of acute exercise on the organism.
There is no right answer because there are various views on the appropriate time as shown in this document, but I think it shows a time that can be used as a reference to some extent.
For those who can't move without the right answer, you may think, "What's that?
As for the intensity of exercise, there are indices such as METS, so it is important to know the intensity of the exercise you are doing.
It's hard to say what the right value is, so why don't you start by trying to reach the median value?
