Effects of Exercise Training on Improving the Immune System of Elderly at the Time of COVID-19: a Systematic Review

This study aimed to investigate the effect of exercise training to improve the immune system of the elderly at the time of COVID-19.

This systematic review study was performed on articles published between 1999 and 2020, and their target group was elderly. Keywords were searched and evaluated by three people in PubMed, Scopus, Science Direct, Google Scholar, Magiran, and SID databases. Twenty-two articles were selected for research.

According to most studieschr('39') results, the leukocyte population decreased significantly or did not change in response to training. In most studies, the levels of T cells (CD3+), helper T cells (CD4+), killer T cells (CD8+), natural killers (CD56+), and B cells (CD19+) did not change. CD28+CD4+ cells after intervention either increased significantly or did not change in some studies. Naive T cells (CD45RA+) and memory T cells (CD45RO+) did not change in the studies. Natural killer cell cytotoxic activity (NKCA) also increased significantly or did not change. Interleukin-6 and tumor necrosis factor-alpha decreased significantly in all related studies, but on the other hand, interleukin-10 increased significantly. The amount of C-reactive protein decreased significantly in the two studies and did not change in the other two studies. Intercellular adhesion molecule-1(ICAM-1), vascular cell adhesion molecule (VCAM-1), and endothelin-1 decreased significantly in investigations. Salivary IgA secretion rate increased significantly in two studies. Salivary IgA concentration increased in two studies and did not change in the other two studies. Salivary IgA flow increased in one study and did not change in another study.

According to the results, regular moderate-intensity exercise training reduces inflammation and improves some safety indicators in the elderly. With immune system improvement through exercise training in the elderly, the ability of the elderly may increase for encountering COVID-19 infection, and the risk of acquiring severe COVID-19 and hospitalization and mortality rates related to this disease may reduce in the elderly.