Exercise And Immune System Pdf
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In this review, we have focused on the effects of exercise on infection or antibody production.
- The compelling link between physical activity and the body's defense system
- Immune Response to Sports
- Stress, Illness and the Immune System
The compelling link between physical activity and the body's defense system
This review summarizes research discoveries within 4 areas of exercise immunology that have received the most attention from investigators: 1 acute and chronic effects of exercise on the immune system, 2 clinical benefits of the exercise—immune relationship, 3 nutritional influences on the immune response to exercise, and 4 the effect of exercise on immunosenescence.
These scientific discoveries can be organized into distinctive time periods: —, which focused on exercise-induced changes in basic immune cell counts and function; —, during which seminal papers were published with evidence that heavy exertion was associated with transient immune dysfunction, elevated inflammatory biomarkers, and increased risk of upper respiratory tract infections; —, when additional focus areas were added to the field of exercise immunology including the interactive effect of nutrition, effects on the aging immune system, and inflammatory cytokines; and to the present, when technological advances in mass spectrometry allowed system biology approaches i.
The future of exercise immunology will take advantage of these technologies to provide new insights on the interactions between exercise, nutrition, and immune function, with application down to the personalized level. Additionally, these methodologies will improve mechanistic understanding of how exercise-induced immune perturbations reduce the risk of common chronic diseases. For example, in , Larrabee 2 provided evidence that changes in white blood cell differential counts in Boston marathon runners paralleled those seen in certain diseased conditions.
The immune system is very responsive to exercise, with the extent and duration reflecting the degree of physiological stress imposed by the workload. This review paper summarizes the research discoveries within 4 areas of exercise immunology that have received the most consideration: acute and chronic effects of exercise on the immune system, clinical benefits of this exercise—immune relationship, nutritional influences on the immune response to exercise, and the exercise effect on immunosenescence Fig.
These scientific discoveries can be organized into distinctive time periods Fig. The earliest exercise immunology studies — focused on exercise-induced changes in basic immune cell counts and function.
Many medical universities acquired flow cytometers in the s, and these instruments became available to exercise investigators, initiating the modern era of exercise immunology research. Another impetus was the publication of a brief review in a special issue of the Journal of the American Medical Association for the Olympic Games in Los Angeles.
During the same time period — , seminal papers were published with evidence that heavy exertion was associated with transient immune dysfunction, elevated inflammatory biomarkers, and an increased risk of upper respiratory tract infections URTIs. During the time period from to , additional focus areas were added to the field of exercise immunology, including the interactive effect of nutrition, 7 , 19 , 20 effects on the aging immune system, 21 , 22 , 23 and influences on inflammatory cytokines.
The acute immune response to exercise depends on the intensity and duration of effort. Exercise immunology investigators had an early focus on the large perturbations of basic leukocyte subsets associated with the physiological stress of athletic endeavor. During moderate- and vigorous-intensity aerobic exercise bouts of less than 60 min duration, the antipathogen activity of tissue macrophages occurs in parallel with an enhanced recirculation of immunoglobulins, anti-inflammatory cytokines, neutrophils, NK cells, cytotoxic T cells, and immature B cells, all of which play critical roles in immune defense activity and metabolic health Fig.
Acute exercise stimulates the interchange of innate immune system cells and components between lymphoid tissues and the blood compartment.
Although transient, a summation effect occurs over time, with improved immunosurveillance against pathogens and cancer cells and decreased systemic inflammation. In general, acute exercise is now viewed as an important immune system adjuvant to stimulate the ongoing exchange of leukocytes between the circulation and tissues.
The measurement of immune responses to prolonged and intensive exercise by athletes continues to receive high attention. Taken together, the best evidence supports that high exercise training workloads, competition events, and the associated physiological, metabolic, and psychological stress are linked to immune dysfunction, inflammation, oxidative stress, and muscle damage.
Although some investigators have challenged the clinical significance and linkage between heavy exertion and transient immune dysfunction, 58 the majority of investigators in the field of exercise immunology have supported the viewpoint that the immune system reflects the magnitude of physiological stress experienced by the exerciser.
The contrast in acute immune responses to heavy exertion e. Recent improvements in mass spectrometry technology and bioinformatics support have improved the capacity to use a systems biology approach when measuring the complex interactions between exercise stress and immune function within the human athlete.
Immune-specific proteins are produced to regulate the innate immune response, with oxylipins involved in initiating, mediating, and resolving this process.
This profound, exercise-induced perturbation in metabolites, lipid mediators, and proteins more than likely has a direct influence on immune function, decreasing the capacity of immune cells to increase oxygen consumption rates after activation.
Although more research is needed, preliminary data support that immune cell metabolic capacity is decreased during recovery from physiologically demanding bouts of intensive exercise, resulting in transient immune dysfunction.
The potential linkage between prolonged, intensive exercise and increased risk for illness has been an active area of research since the s. For example, in a large group of endurance runners, nearly A 1-year retrospective study of German athletes showed that URTI risk was highest in endurance athletes who also reported significant stress and sleep deprivation.
The direct connection between exercise-induced immune changes and infection risk has not yet been established, and will require long-term studies with large cohorts. More research is needed to more clearly demonstrate the linkage between heavy exertion, illness symptoms, and pathogen-based illnesses, and the relative importance of associated factors such as travel, pathogen exposure, exercise-induced immune perturbations, sleep disruption, mental stress, and nutrition support.
As illness data from additional studies mounted, 71 , 72 , 73 , 74 , 75 , 76 , 77 several athletic organizations including the International Olympic Committee IOC and the International Association of Athletics Federation IAAF initiated acute illness surveillance systems to delineate the extent of the problem and underlying risk factors. Load management is a key strategy, according to the IOC, to decrease illness incidence and associated downturns in exercise performance, interruptions in training, missed competitive events, and risk of serious medical complications.
Athletes must train hard for competition and are interested in strategies to keep their immune systems robust and illness rates low despite the physiologic stress experienced. The ultimate objective is to achieve performance goals with little interruption from illness and fatigue from training-induced subclinical immune dysfunction. Several training, hygienic, nutritional, and psychological strategies are recommended, and these require the coordinated involvement of the medical staff, coaches, and athletes.
Adjustments to the guidelines can be applied based on how each individual athlete responds. Here is a summary of the most important guidelines provided from consensus statements: 4 , 6 , 65 , Develop a detailed, individualized training and competition plan that also provides for sufficient recovery using sleep, nutrition, hydration, and psychological strategies. Avoid intensive training when ill or experiencing the early signs and symptoms of illness which can make the illness more severe and prolonged.
Minimize pathogen exposure by avoiding close contact with infected individuals in crowded, enclosed spaces, and not sharing drinking or eating implements. Avoid exercise sessions in poorly ventilated clubs and gymnasium facilities. The medical staff should isolate infected athletes. Limit hand-to-face contact i.
The medical staff should educate the athletes to minimize pathogen spread to others e. Follow other hygienic practices to limit all types of infections including safe sex and the use of condoms, wearing open footwear when using public facilities to limit skin infections, using insect repellents, and covering the arms and legs with clothing at dawn or dusk. Maintain vaccines needed for home and foreign travel, with a focus on annual influenza vaccination.
Consume a well-balanced diet with sufficient energy to maintain a healthy weight, with a focus on grains, fruits, and vegetables to provide sufficient carbohydrate and polyphenols that reduce exercise-induced inflammation and improve viral protection. Follow stress management techniques that decrease the extraneous load of life hassles and stresses.
Develop coping strategies that minimize the internalized impact of negative life events and emotions. Each bout of moderate physical activity promotes improved but transient immunosurveillance and, when repeated on a regular basis, confers multiple health benefits including decreased illness incidence and dampened systemic inflammation.
Table 2 summarizes published evidence from randomized clinical trials and epidemiologic studies on the inverse relationship between moderate exercise training and URTI incidence. The randomized clinical trials 8 weeks to 1 year in length are consistent in demonstrating that study participants assigned to moderate exercise programs experience reduced URTI incidence and duration. The protective effect of moderate activity on illness incidence contrasts with the increased illness risk linked with prolonged and intensive exercise, as summarized in the J-curve model Fig.
J-curve model of the relationship between the exercise workload continuum and risk for upper respiratory tract infection URTI. Other factors such as travel, pathogen exposure, sleep disruption, mental stress, and dietary patterns may influence this relationship.
This figure was adapted from Nieman. Retrospective and prospective epidemiologic studies have measured illness incidence in large groups of individuals engaging in self-selected and varied physical activity workloads Table 2. This relationship persisted, even after adjustment for confounders such as age, education level, marital status, gender, body mass index BMI , and perceived mental stress.
The upper tertiles of fitness and exercise frequency are associated with reduced numbers of days with upper respiratory tract infections URTI. Data from Nieman et al. Physical activity may lower rates of infection for other types of viral and bacterial diseases, but more data are needed.
Several epidemiologic studies suggest that regular physical activity is associated with decreased mortality and incidence rates for influenza and pneumonia. Each exercise bout causes transient increases in total white blood cells, granulocyte-related proteins, and a variety of plasma cytokines including interleukin-6 IL-6 , IL-8, IL, IL, IL-1 receptor antagonist IL-1ra , granulocyte colony stimulating factor, and monocyte chemoattractant protein 1.
Acute phase proteins including C-reactive protein CRP are also increased after heavy exertion, but increases are delayed in comparison with most cytokines. There is increasing evidence that regular exercise training has an overall anti-inflammatory influence mediated through multiple pathways including improved control of inflammatory signaling pathways, release of muscle myokines that stimulate production of IL-1ra and IL perhaps by blood mononuclear immune cells , a decrease in dysfunctional adipose tissue and improved oxygenation, enhanced innate immune function, and an improved balance of oxylipins.
Data are from ongoing studies in the first author's lab during the past 2 decades. The persistent increase in inflammation biomarkers is defined as chronic or systemic inflammation, and is linked with multiple disorders and diseases including obesity, arthritis, atherosclerosis and cardiovascular disease, chronic kidney disease, liver disease, metabolic syndrome, insulin resistance and type 2 diabetes mellitus, sarcopenia, arthritis, bone resorption and osteoporosis, chronic obstructive pulmonary disease, dementia, depression, and various types of cancers.
Epidemiologic studies consistently show reduced white blood cell count, CRP, IL-6, IL, tumor necrosis factor alpha, and other inflammatory biomarkers in adults with higher levels of physical activity and fitness, even after adjustment for potential confounders such as BMI. Most randomized, controlled trials, however, have failed to demonstrate that inflammation is decreased by a clinically significant level with exercise training in the absence of weight loss.
In general, moderate exercise training is unlikely to lower chronic inflammation at the individual level unless the exercise workload is increased to more than min per week and significant weight loss is experienced. Do exercise-induced perturbations in immunity help to explain altered risks of cancer, heart disease, type 2 diabetes, arthritis, nonalcoholic fatty liver disease, and other chronic conditions?
Research in this area is still emergent, but there is increasing evidence that the circulation surge in cells of the innate immune system with each exercise bout and the anti-inflammatory and antioxidant effect of exercise training have a summation effect over time in modulating tumorigenesis, atherosclerosis, and other disease processes. Obesity, the metabolic syndrome, and most common chronic diseases such as atherosclerosis, specific types of cancer, and type 2 diabetes are characterized in part by high inflammation, oxidative stress, and immune dysfunction.
Inflammation involves several types of immune cells, including macrophages and neutrophils, and is an important mediator of oxidative stress. Oxinflammation is a term used to describe the complex interactions between oxidative stress and inflammation. Exercise training has immunomodulating effects that may alter the cross-talk between the immune system and tumorigenesis.
For example, exercise may increase intra-tumoral cytotoxic T-cell infiltration and reduce regulatory T-cell infiltration, enhance the recirculation and function of tumor-specific NK cells, and decrease inflammatory influences that support cancer cell growth. In general, exercise promotes the recirculation of key immune cells and mediates an anti-inflammatory and antioxidant state through multiple mechanisms.
Although many information gaps exist, these exercise-induced effects may help to counter the development of chronic metabolic diseases and are likely multiplied when body fat mass is reduced. The gastrointestinal tract is colonized by trillions of micro-organisms that include a gene set times larger than that of the human genome.
One-third of the adult gut microbiota is similar between most individuals, but diversity is associated with a healthier status.
The gut bacteria composition and diversity is influenced by a variety of factors, including dietary and exercise habits, age, gender, genetics, ethnicity, antibiotics, health, and disease.
The gut microbiota influences human health and immune function, in part through the fermentation of indigestible food components in the large intestine. The microbiome and derived metabolites including short chain fatty acids and biotransformed bile acids have been shown to influence immune function both within the gut and systematically. More human research is needed to establish whether the positive linkage between long-term exercise training and a diverse microbiome translates to improved immune function in physically fit individuals and athletes.
Several comprehensive reviews have been published on the value of nutritional support as countermeasures to exercise-induced immune dysfunction, inflammation, and oxidative stress.
Carbohydrate ingestion before and during exercise attenuates postexercise inflammation. Fruits contain a mixture of sugars and a wide variety of biologically active polyphenols. Polyphenols, in particular flavonoids, have attracted much attention owing to their bioactivity and related health benefits, and new evidence using metabolomics supports their value as potential countermeasures to exercise-induced immune changes. Many of the earlier studies reported few discernable immune-related influences of increased polyphenol intake for athletes, but research design deficiencies portrayed a misunderstanding of polyphenol bioavailability and metabolism, and the appropriate outcome measures.
Polyphenol absorption, disposition, metabolism, and excretion is complex and requires both untargeted and targeted metabolomics procedures to measure small molecule shifts in humans after increased intake. Soon after ingestion, plasma levels of metabolites derived from banana flesh molecules increase, and may confer anti-inflammatory effects by countering cyclooxygenase-2 COX-2 mRNA expression the morning after heavy exertion.
In general, evolving data support the intake of fruits such as dates, raisins, and bananas by athletes during training to provide the sugars and polyphenols that exert anti-inflammatory influences that may enhance metabolic recovery.
Future studies using system-wide approaches such as metabolomics, lipidomics, and proteomics will improve scientific understanding regarding the complex and multilevel interactions between exercise, nutrition, and the immune and metabolic systems. Immunosenescence is defined as immune dysregulation with aging and is related to an increased susceptibility to infections, autoimmune diseases, neoplasias, metabolic diseases, osteoporosis, and neurologic disorders.
Recent evidence supports that immunity can be remodeled during the aging process as a result of interactions with the environment and lifestyle and is instrumental in shaping immune status in later life. Early cross-sectional studies compared immune function in highly conditioned and sedentary elderly men and women.
Immune Response to Sports
Acute viral respiratory infections are the main infectious disease in the world. The immune response to the virus depends on factors such as genetics, age and physical state, and its main input receptor is the angiotensin-converting enzyme 2. The practice of physical exercises acts as a modulator of the immune system. During and after physical exercise, pro- and anti-inflammatory cytokines are released, lymphocyte circulation increases, as well as cell recruitment. Such practice has an effect on the lower incidence, intensity of symptoms and mortality in viral infections observed in people who practice physical activity regularly, and its correct execution must be considered to avoid damage.
By Dr. Saul McLeod updated The immune system is a collection of billions of cells that travel through the bloodstream. They move in and out of tissues and organs, defending the body against foreign bodies antigens , such as bacteria, viruses and cancerous cells. T cells see picture opposite - if the invader gets inside a cell, these T cells lock on to the infected cell, multiply and destroy it.
Moderate physical activity enhances natural killer cell activity and immune function in general (Pedersen and Ullum, ; Nielsen, ), but.
Stress, Illness and the Immune System
Battling another cough or cold? Feeling tired all the time? You may feel better if you take a daily walk or follow a simple exercise routine a few times a week.
This review summarizes research discoveries within 4 areas of exercise immunology that have received the most attention from investigators: 1 acute and chronic effects of exercise on the immune system, 2 clinical benefits of the exercise—immune relationship, 3 nutritional influences on the immune response to exercise, and 4 the effect of exercise on immunosenescence. These scientific discoveries can be organized into distinctive time periods: —, which focused on exercise-induced changes in basic immune cell counts and function; —, during which seminal papers were published with evidence that heavy exertion was associated with transient immune dysfunction, elevated inflammatory biomarkers, and increased risk of upper respiratory tract infections; —, when additional focus areas were added to the field of exercise immunology including the interactive effect of nutrition, effects on the aging immune system, and inflammatory cytokines; and to the present, when technological advances in mass spectrometry allowed system biology approaches i. The future of exercise immunology will take advantage of these technologies to provide new insights on the interactions between exercise, nutrition, and immune function, with application down to the personalized level. Additionally, these methodologies will improve mechanistic understanding of how exercise-induced immune perturbations reduce the risk of common chronic diseases. For example, in , Larrabee 2 provided evidence that changes in white blood cell differential counts in Boston marathon runners paralleled those seen in certain diseased conditions.
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- Я в это не верю. Всем известно, что невзламываемый алгоритм - математическая бессмыслица. Хейл улыбнулся: - Ну конечно… Принцип Бергофского. - А также здравый смысл! - отрезала .
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Он понимал, что времени у него. Агенты могут появиться в любую минуту.