Last updated on May 24, 2019 at 19:43
When you stand up suddenly from a sitting or supine position, you may experience the feeling of seeing stars, feeling dizzy and losing consciousness. This happens when your body don’t get enough time to adapt, and the blood pressure drops.
Normally going from a supine to orthostatic posture results in arteriolar and venous constriction caused by fast baroreceptor-triggered sympathetic vasoconstriction, which reduces the volume of blood that is “stored” in veins and brings this blood back to the functional circulation, to not lose blood pressure.
If a person has hypotension these mechanisms may not be fast enough to restore blood flow if you stand up fast enough. The result can be that the brain receives reduced blood flow for some seconds while the blood pressure increases.
We’re more predisposed to orthostatic hypotension in:
- Hot environments (skin vasodilation)
- Any condition that decreases sympathetic activity
- Diabetic neuropathy
- Alcoholic neuropathy
- Uremic neuropathy
- Antihypertensive or diuretic drugs
It can be dangerous if you lose consciousness and fall on something and hit your head, but otherwise it’s pretty benign.
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