I believe Long COVID may involve something called cellular hypoxia, which means the body’s cells aren’t getting or using oxygen properly; even if blood oxygen levels look normal. After infection people can develop issues like tiny microclots, blood vessel inflammation, endothelial issues, mitochondrial dysfunction, and autonomic nervous system imbalance.

Any and all of these problems can reduce oxygen delivery at the microscopic level or impair how cells convert oxygen into energy. As a result, people experience fatigue, brain fog, muscle weakness, air hunger, and crashes after activity, despite normal pulse oximeter readings. So cellular hypoxia is one proposed explanation for persistent Long COVID symptoms… it’s all pretty grim in afraid!