Potential Physiological and Cellular Mechanisms of Exercise That Decrease the Risk of Severe Complications and Mortality Following SARS-CoV-2 Infection

Abstract

The coronavirus disease 2019 (COVID-19) pandemic caused by severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) has unmasked mankind’s vulnerability to biological threats. Although higher age is a major risk factor for disease severity in COVID-19, several predisposing risk factors for mortality are related to low cardiorespiratory and metabolic fitness, including obesity, cardiovascular disease, diabetes, and hypertension. Reaching physical activity (PA) guideline goals contribute to protect against numerous immune and inflammatory disorders, in addition to multi-morbidities and mortality. Elevated levels of cardiorespiratory fitness, being non-obese, and regular PA improves immunological function, mitigating sustained low-grade systemic inflammation and age-related deterioration of the immune system, or immunosenescence. Regular PA and being non-obese also improve the antibody response to vaccination. In this review, we highlight potential physiological, cellular, and molecular mechanisms that are affected by regular PA, increase the host antiviral defense, and may determine the course and outcome of COVID-19. Not only are the immune system and regular PA in relation to COVID-19 discussed, but also the cardiovascular, respiratory, renal, and hormonal systems, as well as skeletal muscle, epigenetics, and mitochondrial function.

Physical Activity Modifies the Severity of COVID-19 in Hospitalized Patients—Observational Study

“…Just before the COVID-19 pandemic, information on the impact of exercise on the human immune defense was published [ 42 ]. Unfortunately, the general impact of PA on infectious disease morbidity and severity was not analyzed as a pure variable but in the context of body composition (reduction of excess body mass) up to now.…”

Blood Profiling of Athletes after COVID-19: Differences in Blood Profiles of Post-COVID-19 Athletes Compared to Uninfected Athletic Individuals—An Exploratory Analysis

“…Given the beneficial effects of regular exercise and high levels of cardiovascular fitness, together with increasing evidence for lowered COVID-19 severity and mortality in athletes [44,45], more focus on COVID-19 treatments should pertain to preventive measures such as physical exercise and maintaining a normal body weight and be prescribed and advised by all health care practitioners. As we observed in the sex-divided analyses, more differences were observed between the ATH and HC groups for the women (25 different variables, for example: absolute lymphocyte, MCH, TNF-alpha, potassium, and vitamin B6) than for the men (five different variables: TSH, uric acid, troponin-T, potassium and vitamin D 25OH), and sex-specific differences should always be kept in mind.…”

Age‐related differences in symptoms in older emergency department patients with COVID‐19: Prevalence and outcomes in a multicenter cohort

“… 37 In addition to presenting with confusion, older adults with COVID‐19 may be afebrile 38 and may lack cough or chest discomfort, thus any change in their clinical status from baseline warrants COVID‐19 testing. 39 In addition to delirium and atypical presentations of disease, several mechanisms could explain increased susceptibility to severe COVID‐19 including age‐related immunosenescence, 5 chronic inflammatory states due to dementia or other comorbidities, 40 , 41 , 42 less aggressive treatment due to age bias or preexisting code status, and greater avoidance of EDs during the pandemic. 6 The original study variables did not include DNR/DNI status, which is more frequent in older adults and could also confound the association between age and illness severity.…”

“…Adults aged 65 years and older are 8.7 times more likely to require hospitalization for SARS‐CoV‐2 infection, and have accounted for 22% of cases and 78% of deaths related to COVID‐19 in the United States. 1 Older adults are thought to have unique vulnerability to COVID‐19 due to a higher comorbidity burden, 2 , 3 , 4 greater clinical frailty, 5 access to care challenges, 6 and immunosenescence, 5 , 7 all which could explain their greater likelihood of morbidity and mortality. Another possible explanation is that diagnoses of COVID‐19 could be missed in older adults due to less common presenting symptoms leading to treatment delay.…”