The Role of Exercise and Physical Activity against COVID-19: A Narrative Review Study

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Extended Abstract
Background and Objectives
Since COVID-19 virus is an unknown virus which has caused alarming death toll over the past year, researchers felt impelled to take measures through doing extensive research studies in a variety of related fields to control the virus. On the other hand, exercise is known as a useful non-pharmacological method to improve the function of the immune system, so researchers in the field of sports science have done valuable research studies in this research domain, albeit limited, which can provide us with valuable information in this regard. Hence, there is a pressing need to collect and categorize these latest findings. Therefore, the very aim of this study was to review literature on the role of exercise and physical activity against the COVID-19.
Material and Methods
This was a narrative review, the data was collected through searching and retrieving available articles published in databases like Medline (PubMed), Scopus, ScienceDirect, and also Google Scholar. The keywords employed for search strategy building included: "exercise training", "physical activity", "aerobic exercise", "interval training", "resistance training", "endurance training", "COVID-19", "novel coronavirus" and "immune system". Based on the results of our searches conducted in databases, initially 1185 articles were selected. After screening the titles and abstracts of the retrieved articles and removal of the duplicate and irrelevant ones, 59 articles were included in the review stage. Then, full text of eligible articles were put underclose scrutiny which led to the final selection of only 28 articles to be studied.
Results
According to our review, exercise can play a role in different ways against COVID-19 diseases and novel coronavirous, which is now recognized as a global problem. These roles include preventing some underlying diseases such as hypertension, coronary artery disease and diabetes and improving immunity. Exercise lowers cortisol levels in long term, which reduces the stress induced by COVID-19, which in turn strengthens the immune system. On the other hand, doing moderate- intensity exercise can strengthen the immune system in the long run, while low-intensity or high-intensity exercise types do not bring about similar degree of adaption.
Conclusion
It is necessary to pay special attention to exercise training in COVID-19 pandemic period. However, it should be noted that due to the novelty of this phenomenon, limited research has been done in this area to date and more research studies are required to be done in this regard.
Practical implications of research
It is best for people to stay home during COVID-19 pandemic period and to have 150 minutes of moderate-intensity regular exercise during the week to boost their immune system.
Ethical considerations
In this review research, the ethical issues of research and fiduciary have been observed.
Conflict of interest
We have no conflicts of interest to declare.
Acknowledgment
No sources of funding were used to assist in the preparation of this article.