ACE2 and COVID-19: If aerobic exercise lowers ACE1 activity, it is probable that it may lead to a high ACE2/ACE1 ratio, and as RAS is subject for local tissue homeostasis by anti-inflammatory, anticoagulant, and anti-proliferation, it may control the local trophic responses to viruses (Tikellis and Thomas, 2012), possibly COVID-19.