Post-Covid: physical exercise is an ally in muscle recovery

The virus goes away, the sequelae remain: cardiorespiratory difficulties, muscle weakness, fatigue and tiredness have been symptoms frequently reported by people who have been through covid-19 – it is skeletal myopathy. A USP study revealed that physical exercise – especially aerobic exercise – can reverse the condition, rescuing the functionality of a crucial enzyme that is affected by the coronavirus, the angiotensin II-converting enzyme (ECA2).

Study indicates that exercises are allies in the recovery of covid-19.Source: Pixabay

“The ECA2 enzyme functions as a receptor on the cell membrane and serves as a gateway for SARS-CoV-2, that is, protein S [spike ou espícula] the virus recognizes and binds directly to the ECA2 receptor, ”explained Professor Edilamar Menezes de Oliveira to the USP Journal, coordinator of the Exercise Biochemistry and Molecular Biology Laboratory at USP’s School of Physical Education and Sport (EEFE).

The researcher explained that, when entering the cells, the virus damages the structure of ECA2, taking away its functionality in balancing the Renina Angiotensin System (RAS), which is crucial to regulate various processes in the body. “What physical exercise does, especially aerobic activity, is to recover this functionality”, he said.

ECA2: how it works

The ECA2 enzyme converts angiotensin II (Ang II) – associated with cardiovascular diseases such as hypertension, arteriosclerosis and myocardial infarction – into angiotensin 1-7 (Ang-1-7), which is “good”: it does the opposite of dangerous substance in the SARS, avoiding harmful effects to the cardiovascular system.

The researcher explained that ECA2 is present in many tissues of the body, such as skeletal musculature – and therefore it compromises several organs when someone is infected by the coronavirus: it affects the muscles of the chest, and may contribute to ventilatory failure, in addition to oxygenation, due to pneumonia. “The increase in the expression of this molecule (ECA2) in patients can even influence the severity of the disease,” he said.

Distribution of the ECA2 enzyme in the human body.Distribution of the ECA2 enzyme in the human body.Source: USP Journal / Reproduction.

In 2010, a survey of obese rats under the guidance of Edilamar had already shown that after physical training consisting of five weekly sessions of 60 minutes for ten weeks, the animals achieved improvement in several indices: increased ECA2 enzyme in the heart, reduced heart rate body weight, triglycerides and heart rate, in addition to lowering LDL (bad cholesterol) and increasing HDL (good cholesterol). And humans can also benefit from this.

How the enzyme helps our body

But what, after all, is the SRA that ECA2 works balancing? It is a system that works to maintain the correct blood pressure, balancing the amount of water and salt in the body. If it is not working well, this regulation affects the functioning of other organs, such as the heart, blood vessels, kidneys and skeletal muscle.

Professor Tiago Fernandes, one of the researchers at the Biochemistry Laboratory, explained to the USP newspaper that the regulation of SRA is made by two enzymes: ECA1 and ECA2. They fulfill inverse roles of compensation. The first promotes vasoconstriction – the increase in blood pressure; and the second, vasodilation – with a decrease in blood pressure.

System regulated by the ECA2 enzyme helps to regulate blood pressure.System regulated by the ECA2 enzyme helps to regulate blood pressure.Source: Pixabay

Then the SARS is activated when the pressure is too low or when there is a lot of fluid loss: it starts a series of reactions for the organs to stabilize again.

Mice deficient in ECA2 receptors exhibit cardiac dysfunctions such as increased blood pressure, myocardial tissue degeneration, endothelial dysfunction (type of arterial disease), increased risk of intravascular thrombosis, chronic kidney disease, metabolic abnormalities and several other abnormalities in the regulation of the system cardiovascular. When ECA2 is activated, harmful effects on cells and organisms are prevented.

For Professor Edilamar, there are still many unanswered questions about SARS-CoV-2 infection, but understanding the features of ECA2, which plays a major role in the mechanism of virus entry into the body, is fundamental for understanding the changes that occur in the body due to the disease.

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