Objective: This review was conducted to systematically analyze the effects of aerobic exercise on immunological biomarkers to provide safe aerobic exercise recommendations and specifications for patients with COVID-19.
Materials and methods: A systematic search was conducted through MEDLINE (PubMed), Science Direct, Web of Science, Scopus, Cochrane Library, and SciELO databases. The search included the following keywords "immune system", "immune cell", or "immune function"; "aerobic training", "aerobic exercise", or "physical activity"; "human" or "adult"; and "cytokine", "killer cell", "T cell", "interleukin", "lymphocyte", "leukocyte" or "adhesion molecule".
Results: Eleven studies met the inclusion and exclusion criteria of this search. The most used exercise prescriptions included walking, cycling, or running. The duration of exercise ranged from 18 to 60 min with an intensity of 55% to 80% of VO2max or 60%-80% of maximum heart rate. The frequency range was 1 to 3 times/week. The mainly increased immunological biomarkers included leukocytes, lymphocytes, neutrophils, monocytes, eosinophils, IL-6, CD16-56, CD16, CD4, CD3, CD8, and CD19.
Conclusions: This review demonstrated that patients with COVID-19 should follow a regular program of aerobic exercise for 20-60 min. This program should be in the form of cycling or walking with an intensity of 55%-80% VO2max or 60%-80% of maximum heart rate. This program should be repeated 2-3 sessions/week. These previous parameters could safely enhance immune functions without producing any exhaustion.