Potential Improvement in Rehabilitation Quality of 2019 Novel Coronavirus by Isometric Training System; Is There “Muscle-Lung Cross-Talk”?

Abstract

The novel Coronavirus Disease 2019 (COVID-19) crisis is now present in more than 200 countries. It started in December 2019 and has, so far, led to more than 149, 470,968 cases, 3,152,121 deaths, and 127,133,013 survivors recovered by 28 April 2021. COVID-19 has a high morbidity, and mortality of 2%, on average, whereas most people are treated after a period of time. Some people who recover from COVID-19 are left with 20 to 30% decreased lung function. In this context, exercise focused on skeletal muscle with minimal lung involvement could potentially play an important role. Regular exercise protects against diseases associated with chronic low-grade systemic inflammation. This long-term effect of exercise may be ascribed to the anti-inflammatory response elicited by an acute bout of exercise, which is partly mediated by muscle-derived myokines. The isometric training system seems to have this feature, because this system is involved with the skeletal muscle as the target tissue. However, no studies have examined the effect of exercise on the treatment and recovery of COVID-19, and, more importantly, “muscle–lung cross-talk” as a mechanism for COVID-19 treatment. It is suggested that this theoretical construct be examined by researchers.

Moderate Intensity Aerobic Exercise Potential Favorable Effect Against COVID-19: The Role of Renin-Angiotensin System and Immunomodulatory Effects

“…Also, by accumulation of neutrophils, the creation of ROS and pro-inflammatory molecules raises ( Yan and Spaulding, 2020 ), which are associated with acute lung injury, the most common cause of morbidity and mortality in COVID-19 ( Nobari et al, 2021b ). Mitochondria is a place for ROS production and exercise is a potent mediator of ROS ( Nobari et al, 2021a ). Irisin is a skeletal muscle myokine ( Nobari et al, 2021a ), which could play a role in anti-oxidative pathways involving the transcription factor nuclear factor erythroid 2-related factor 2 (Nrf2) ( Wang et al, 2016 ), and even on the expression of many distinct genes related to SARS-CoV-2 infection ( de Oliveira et al, 2020 ).…”

“…Mitochondria is a place for ROS production and exercise is a potent mediator of ROS ( Nobari et al, 2021a ). Irisin is a skeletal muscle myokine ( Nobari et al, 2021a ), which could play a role in anti-oxidative pathways involving the transcription factor nuclear factor erythroid 2-related factor 2 (Nrf2) ( Wang et al, 2016 ), and even on the expression of many distinct genes related to SARS-CoV-2 infection ( de Oliveira et al, 2020 ). Irisin has a positive correlation with improved lung function ( Nobari et al, 2021b ).…”

“…During the acute phase of infection, exercise may cause increased viral replication, an intense pro-inflammatory response ending in heightened cellular necrosis ( Kiel et al, 1989 ). After COVID-19 disease, due to the spread of infection, the patients will not be able to exercise ( Zhu et al, 2020 ; Nobari et al, 2021a ). Hence, it was recommended to cease exercise in case of active COVID-19 infection and the presence of any of the following symptoms: severe sore throat, body aches, shortness of breath, general fatigue, chest cough, or fever ( Zhu, 2020 ).…”

“…Inpatient rehabilitation for patients with COVID-19 was associated with significant functional and respiratory enhancement, especially in severe cases ( Piquet et al, 2021 ). Also, a recent study proposed that rehabilitation and breathing exercises in patients are effective in preventing muscle atrophy or at least its rapid progression ( Nobari et al, 2021a ). A systematic review with meta-analyses showed that aerobic training combined with breathing exercises led to significant advancement in exercise capacity, dyspnea, and quality of life in patients with idiopathic pulmonary fibrosis ( Hanada et al, 2020 ).…”

“…Nevertheless, because of respiratory tract infection, achieving aerobic exercises for patients with COVID-19 would be exceedingly tough. Accordingly, skeletal muscle exercise with minimum lung involvement such as isometric training (muscle contraction with muscle-tendon unit at a constant length), which includes 5–10 repetitions of 5 s per contraction, 5 days per week should be preferred ( Khoramipour et al, 2021 ; Nobari et al, 2021a ).…”