Figure 1. The effects of aging on the organism and its relationship with COVID-19-associated deterioration. Aging patients are more susceptible to SARS-CoV-2, which leads to the exacerbation of COVID-19. Aging has a negative impact on the human organ system, causing its functional decline. The aging process is accompanied by a state of low-grade inflammation, and the elderly are more susceptible to SARS-CoV-2 infection. Under the influence of the virus, the damage to infected aging patients is further worsened, resulting in serious secondary diseases. In the figure, "↑" means the number increases, the function or effect is enhanced; "↓" means the number decreases, the function or effect is weakened. ERS: endoplasmic reticulum stress; ACE2: angiotensin-converting enzyme 2; TMPRSS2: transmembrane protease serine 2; ADAM17: a disintegrin and metalloprotease 17; ARDS: acute respiratory distress syndrome; AKI: acute kidney injury; PKC: protein kinase C; ROS: reactive oxygen species; CKD: chronic kidney disease; DIC: disseminated intravascular coagulation.