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Postural orthostatic tachycardia syndrome (POTS) is one of a group of disorders that have orthostatic intolerance (OI) as their primary symptom.OI describes a condition in which an excessively reduced volume of blood returns to the heart after an individual stands up from a lying down position.n POTS, the lightheadedness or fainting is also accompanied by a rapid increase in heartbeat of more than 30 beats per minute, or a heart rate that exceeds 120 beats per minute, within 10 minutes of rising. The faintness or lightheadedness of POTS are relieved by lying down again.
The condition is so named because those who suffer from it have a heart that's too small. The medical term for the condition is POTS, short for postural orthostatic tachycardia syndrome. About 500,000 in the U.S., mostly young women, are affected. Among other symptoms, those with POTS have a rapid increase in their heartbeat when they change from lying down to standing. The volume of blood pumped out from the heart with each beat is low. That can make it difficult to stand for long periods. Quality of life can suffer greatly.