(HealthDay News) -- When some people stand up quickly, they have a severe drop in blood pressure that can cause dizziness or fainting.
Normally, when you go from sitting to standing, your nervous system temporarily compensates by narrowing your blood vessels and increasing your heart rate. This is supposed to prevent a sudden drop in blood pressure, the Mayo Clinic says.
But sometimes, a person's blood pressure drops anyway. Some possible causes include:
- Aggressive use of blood pressure-lowering medications, or use of other medications that have the same effect.
- Irregular heartbeat, a condition known as heart arrhythmia.
- Severe dehydration.
- Prolonged bed rest.
Treatments may include medication to raise blood pressure, avoiding triggers such as dehydration, and even use of support stockings.