Volume 3 | Issue 5 | 1 of 2 Int J Psychiatr Res, 2020 COVID-19 Pandemic: How Can Exercise Help the Old Immune System? 1 Postgraduate Program of Health Sciences, Montes Claros State University, Montes Claros, Minas Gerais, Brazil. 2 Rio de Janeiro State University, Rio de Janeiro, Brazil. 3 University Institute of Maia (ISMAI), Maia, Portugal. 4 Research Centre in Sports Sciences, Health Sciences and Human Development, CIDESD, GERON Research Community, Portugal. 5 Higher Institute of Educational Sciences (ISCE, Douro), Penafel, Portugal. Renato Sobral Monteiro-Junior, PhD 1 , Rodrigo Terra, PhD 2 , Mariléia Chaves Andrade, PhD 1 , and Lara S. F. Carneiro, PhD 3,4,5,* International Journal of Psychiatry Research ISSN 2641-4317 Review Article Citation: Renato Sobral Monteiro-Junior, Rodrigo Terra, Mariléia Chaves Andrade, et al. COVID-19 Pandemic: How Can Exercise Help the Old Immune System?. Int J Psychiatr Res. 2020; 3(5): 1-2. Keywords COVID-19, Infection, Immune system. Background COVID-19 is a disease caused by a coronavirus infection, the SARS-CoV-2. It has become a worldwide concern, especially to older adults and persons with chronic diseases [1]. Older adults have a less active immune response to stressors than young persons, which is a risk factor for infections. Furthermore, older adults with a noneffective immunological response present a slow recovery after an infection [2]. This work aims to clarify how exercise alters the immune system and prevents complications from COVID-19 in older persons. We approached the text with topics to provide a better comprehension of the subject. A brief view of the immune system and immunosenescense The bipolar aspect of the immune system is characterized by innate and adaptive responses. The innate response includes the participation of macrophages, neutrophils, dendritic cells, natural killer cells (NK) and microbicidal molecules such as nitric oxide (NO), complement system and superoxide anion (O2-). The acquired immune response mainly involves T lymphocytes (TCD4+ and TCD8+), B lymphocytes and their products, cytokines and antibodies, respectively. It can be divided into humoral (mediated by antibodies) and cellular immune responses (mediated by cells, such as T lymphocytes and macrophages). TCD4+ lymphocytes (Th0 helper) can differentiate into several subpopulations such as Th1 cells (T helper type 1). The differentiation of TCD4+ lymphocytes into Th1 can be stimulated by interleukin 12 (IL-12), produced by antigen - presenting cells (macrophages and dendritic cells). Th1 cells produce predominantly gamma interferon (IFN-γ) and are related to the control of intracellular infections, such as viruses [1,2]. The aging process is marked by the decline of many physiological functions, including some immune functions and the accumulation of senescent cells [3]. The aging of the immune system, named immunosenescence, can play a key role in the development of COVID-19 infection. The decrease in B lymphocytes in older people, due to the decrease in hematopoiesis in the bone marrow, and in T lymphocytes (T CD4+ e T CD8+) due to the involution of the thymus, as well as a decrease in the export of Naive T cells to the lymph nodes, compromises the adaptive immune response [1]. This couples with the decline of innate immunity cells, such as neutrophil phagocytosis and chemotaxis. Antigen presentation by macrophages and the production of type I interferons by dendritic cells may contribute to a serious condition of the disease [1]. On the other hand, it has been shown that with aging there is an accumulation of senescent cells, which are sources of proinfammatory cytokines and chemokines induced by viral infections This can be part of the mechanisms that explain the hyperinfammation observed in severe COVID-19 elderly patients. It is reasonable to propose that these overlapping phenomena (immunosenescense and senescent cells) may contribute to aggravate the condition of elderly patients with comorbidities [3]. Chronic low-grade infammation associated either with the aging * Correspondence: Lara Sofa Rodrigues de Sousa Fernandes Carneiro, Research Centre in Sports Sciences, Health Sciences and Human Development, CIDESD, GERON Research Community, Portugal. Received: 20 August 2020; Accepted: 25 September 2020