Mood changes and “brain fog” experienced during COVID-19 illness and recovery may stem in part from blood vessel damage and impaired oxygen delivery caused by the disease, suggests a review published in Physiological Reports.
“This review examines how capillary damage and inflammation may contribute to these acute and persisting COVID‐19 symptoms by interfering with blood and tissue oxygenation and with brain function,” wrote Leif Østergaard, MD, PhD, a neuroradiology researcher at Aarhus University Hospital, Denmark.
Even after acute COVID-19 has passed, ongoing symptoms such as an inability to concentrate, memory problems, anxiety, and depression have been reported by patients.
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The review explains that people with COVID-19 have a reduced blood flow transit time in the capillaries that limits the amount of oxygen that can be delivered to their lungs and brain. Lowered oxygen levels, combined with an increase in inflammatory cytokines with SARS CoV-2 infection, could lead to reduced serotonin levels in people with COVID-19, causing the mood and cognitive changes reported by patients.
According to the paper, COVID-19 recovery may rely on the restoration of normal blood flow through the capillaries.
“SARS‐CoV‐2‐related inflammation and capillary damage may contribute synergistically to acute and long‐term COVID‐19 symptoms by interfering with blood and tissue oxygenation,” Dr. Østergaard wrote. “Further studies of microvascular changes during COVID‐19—and especially subsequent capillary repair—are needed to understand capillary dysfunction’s impact on the acute and chronic health effects of the disease.”
—Jolynn Tumolo
References
Østergaard L. SARS CoV-2 related microvascular damage and symptoms during and after COVID-19: consequences of capillary transit-time changes, tissue hypoxia and inflammation. Physiological Reports. 2021;9(3):e14726.