What is Vasoconstriction? What is Vasodilation?

If you have POTS, you’ve probably heard these two terms- vasoconstriction & vasodilation.

What is Vasoconstriction & Vasodilation?

Vasoconstriction is the constriction, or tightening, of blood vessels- things get tighter and blood is able to be pushed back up against gravity. In other words, vasoconstriction is the narrowing (constriction) of blood vessels by small muscles in their walls. (1) Vasoconstriction is often associated with increased blood pressure.

Vasodilation is the relaxation of blood vessels. Things get looser, and blood is able to flow more freely (if there is enough of it), or it can pool if there isn’t enough vasoconstriction to counteract gravity. Vasodilation is caused by the muscles in the walls of the blood vessels relaxing. Vasodilation is often associated with reduced blood pressure.

Why Should I Care?

As you can see above, vasoconstriction and vasodilation directly impact blood flow and blood pressure. A subset of POTS is caused by chronic vasodilation, which can be helped by vasoconstriction. Another subset of POTS is hypothesized to be caused by low blood volume, which vasoconstriction can help compensate for.

For some folks with low blood pressure, adding a medication that is a vasoconstrictor can help alleviate symptoms. Likewise, if high blood pressure is an issue, sometimes a vasodilator can help. It’s also hypothesized that some brain fog, if caused by low blood volume or vasodilation, can be helped by vasoconstriction. For me personally, understanding these concepts just helps me understand a bit more what’s going on with my body.

Fun fact: caffeine is a natural vasoconstrictor. That’s why it’s often used for energy & migraines.


  1. Mount Sinai,%2C%20drugs%2C%20or%20psychological%20conditions.

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