Exercise and the Immune System

https://doi.org/10.1016/j.csm.2007.04.011Get rights and content

Exercise has a variable effect on the immune system. The underlying reasons for this variability are multifactorial and include infectious, neuroedocrine, and metabolic factors, with nutritional status of the athlete and the training load playing a role. Environmental factors such as living quarters, travel requirements, and the type of sport (team versus individual) also contribute to infectious risk. Regarding the direct effect of exercise on the immune system, moderate exercise seems to exert a protective effect, whereas repeated bouts of strenuous exercise can result in immune dysfunction. Understanding the relationship between exercise and infectious disease has important potential implications for public health and for clinicians caring for athletes and athletic teams.

Section snippets

The Immune System

The immune system is very complex and essential for maintaining health. Dysfunction can lead to a wide variety of diseases. The immune system comprises two basic components: the innate immune system and the adaptive immune system. Elements of the innate system include exterior defenses (such as the skin and mucous membranes), nonspecific phagocytic leukocytes, and serum proteins [4]. Pathogens that escape these initial outer barriers then come in contact with the adaptive system, which is made

The Innate System

The largest organ in the body, the skin, provides the initial blockade to infection. Many natural openings to body cavities and glands, however, provide entry for infectious agents. Protection at these sites is provided in the form of mucus, enzymes, and secretory immunoglobulins. Certain organs such as the lung and stomach also prevent entrance into the bloodstream. Characteristics specific for these organs, such as alveolar macrophages and low pH, respectively, provide protection from further

The Adaptive System

The adaptive system provides its skill of fending off invaders by three unique methods. The first is the ability to recognize antigenic markers on specific pathogens. The second is the ability to supply a cellular and molecular assault on the invading organisms. The final aspect of this destructive triad is the capability of recalling previous invaders, which in turn accelerates and potentiates subsequent responses to the same agent or antigen. The cells that compose the adaptive system are

Sports Immunology

Sports immunology is a relatively new field that examines the interaction of physical, psychologic, and environmental stress on immune function. Over the last 100 years, there have been more than 600 articles published in this area. Most (>60%) have been published since 1990. As late as 1984, some investigators believed that “there is no clear experimental or clinical evidence that exercise will alter the frequency or severity of human infections” [4]. More recently, clinicians and scientists

Impact of Exercise on the Immune System

A large bank of scientific, clinical, and epidemiologic data supports the concept of positive and negative impacts of exercise on the immune system, including the American College of Sports Medicine position papers and the Surgeon General's report on physical activity and health. These effects are highly variable, depending on the nature and intensity of exercise. Currently, the authors define vigorous exercise as 5 to 60 minutes at 70% to 80% aerobic capacity and moderate exercise as 5 to 60

The Cellular Effects of Exercise

The specific cause for the difference in URTI incidence has been demonstrated on a microscopic level. Cellular response to physical activity is seen with natural killer cell activity, neutrophil function, and lymphocytic response. Several studies have reproduced this concept; however, few have related the actual cellular response to the presence of clinical disease. There has been a great deal of research into the effects of exercise on secretory immunoglobulins, specifically IgA. As described

Cancer and Exercise

Over 100 epidemiologic studies suggest that routine exercise is associated with a reduction of cancer, specifically colon and breast cancer [19]. Simple moderate activity such as mowing the lawn has shown a primary preventive protective benefit compared with activities of less intensity [20]. The evidence regarding secondary prevention is not as compelling but reveals some benefit associated with risk of death from breast cancer. Again, breast and colon cancer patients who exercise appear to

Aging, Gender, Exercise, and Immunity

As the body ages, disease is able to establish a foothold more easily than in the younger years. The body's innate ability to respond to and recover from foreign insult begins to waiver. A number of studies have revealed decreased T-cell response to pathogens in elderly subjects compared with young subjects [21], [22]. It is difficult to isolate deconditioning from the ageing process as a primary cause of a dysfunctional immune system. This decrimental progression is known to be multifactorial

Immunologic Nutritional Concerns

It has been proposed that nutrient supplementation may enhance the immune system, benefiting the transient immunosuppression seen from intensive training. This detrimental effect on the immune system may be related to the increased oxygen use during stressful activity, leading to the excessive production of free radical production. Therefore, research has been directed at antioxidatant therapy such as vitamin C and vitamin E. In addition, data have been collected regarding the effect of

Summary

What does this mean for one's patients? All patients must be considered athletes because everyone undergoes various stressors of daily living that most likely affect the immune system in ways similar to intensive exercise. We must continue to appreciate the impact of stress and the environment on immune system function. When counseling patients, attention should be given to that patient's mental, social, and physical stress levels. It is prudent that emphasis be given to the role of moderately

References (29)

  • B.B. Pershin et al.

    Reactions of immune system to physical exercises

    Russ J Immunol

    (2003)
  • L.T. Mackinnon et al.

    The effect of exercise on secretory and natural immunity

    Adv Exp Med Biol

    (1987)
  • M.M. Fahlman et al.

    Mucosal IgA and URTI in American college football players: a longitudinal study

    Med Sci Sports Exerc

    (2005)
  • A.P. Novas et al.

    Tennis, incidence of URTI and salivary IgA

    Int J Sports Med

    (2003)
  • Cited by (0)

    View full text