Sleep apnea and hypertension

[anbuitachi]

How does sleep apnea cause systemic and pulmonary hypertension?
I read one source that said it's because it causes systemic vasoconstriction due to high CO2 and low O2.. but i'm confused since doesn't CO2 lead to vasodilation???

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[Wolverines83]

How does sleep apnea cause systemic and pulmonary hypertension?
I read one source that said it's because it causes systemic vasoconstriction due to high CO2 and low O2.. but i'm confused since doesn't CO2 lead to vasodilation???

apnea = no ventilation = "hypoxic" alveoli = vasoconstriction (unique to pulmonary vasculature) = more pulm resistance ---> HTN via endo damage and repair (like systemic)

 

[loveoforganic2]

Sleep apnea is also associated w/increased SNS activation iirc

 

[anbuitachi]

oh i see thanks

 

[SLC]

apnea = no ventilation = "hypoxic" alveoli = vasoconstriction (unique to pulmonary vasculature) = more pulm resistance ---> HTN via endo damage and repair (like systemic)

This is the answer, and it's a pretty cool adaptation that's at play. It's unique to the pulmonary circulation.

Basically, with decreased PAO2, a hypoxic vasoconstriction is triggered that serves to shunt blood to areas of the lung that have adequate ventilation. It's the body's way of trying to be efficient, but it causes a net decrease in the cross sectional area for blood to flow through in the lungs, increasing vascular resistance and resulting in pulmonary HTN.

 

[MDSlacker]

The hypoxia also induces the release of erythropoietin which contributes to the systemic hypertension.