R E V I E W Immunological outcomes of exercise in older adults David S Senchina1 Marian L Kohut2 1Biology Department, Drake University, Des Moines, IA, USA 2Gerontology Program, Department of Health and Human Performance, Iowa State University, Ames, IA, USA Correspondence: Marian L Kohut 246 Forker Building, Department of Health and Human Performance, Iowa State University,Ames, Iowa, 50011-1160, USA Tel +1 515 293 8364 Fax +1 515 294 8740 Email mkohut@iastate.edu Abstract: Aging is associated with a dysregulation of the immune system known as immu- nosenescence. Immunosenescence involves cellular and molecular alterations that impact both innate and adaptive immunity, leading to increased incidences of infectious disease morbidity and mortality as well as heightened rates of other immune disorders such as autoimmunity, cancer, and inﬂammatory conditions. While current data suggests physical activity may be an effective and logistically easy strategy for counteracting immunosenescence, it is currently underutilized in clinical settings. Long-term, moderate physical activity interventions in geriatric populations appear to be associated with several beneﬁts including reduction in infectious disease risk, in- creased rates of vaccine efﬁcacy, and improvements in both physical and psychosocial aspects of daily living. Exercise may also represent a viable therapy in patients for whom pharmacological treatment is unavailable, ineffective, or inappropriate. The effects of exercise impact multiple aspects of immune response including T cell phenotype and proliferation, antibody response to vaccination, and cytokine production. However, an underlying mechanism by which exercise affects numerous cell types and responses remains to be identiﬁed. Given this evidence, an increase in the use of physical activity programs by the healthcare community may result in improved health of geriatric populations. Keywords: exercise, immunosenescence Introduction Aging is associated with numerous physiological changes. Immunosenescence is a term coined to represent changes to the immune system associated with aging. While most studies have focused on age-related declines in immune function, it is more accurate to think of immunosenescence as a state of dysregulation because lymphocytes respond heterogeneously to aging. From a clinical standpoint, immunosenescence impacts directly on morbidity and mortality. Older adults constitute the fastest growing population in the US. Compared with young or middle-aged adults, older adults exhibit heightened incidences of infec- tious disease, particularly inﬂuenza, pneumonia, and urinary tract infections (Bender 2003; Falsey and Walsh 2005; High et al 2005; Nichol 2005). Infectious diseases are also a major cause of death in the elderly. Perhaps the most intuitive strategy for reducing these infections in the elderly is vaccination if available. Vaccination of older adults against these pathogens and others is effective at reducing morbidity and mortality (Mangtani et al 2004; Meyer 2001); however, elderly individuals exhibit much lower response and recall rates to numerous bacterial (eg, pneumonia, tetanus) and viral (eg, inﬂuenza, polio) vaccines as compared with younger counterparts (Castle 2000; El Yousﬁ et al 2005; Grubeck- Loebenstein et al 1998; McElhaney 2003; Nichol 2005). While immensely beneﬁcial, Clinical Interventions in Aging 2007:2(1) 3–16 © 2007 Dove Medical Press Limited.All rights reserved 3