Postural orthostatic tachycardia syndrome, often abbreviated as POTS, is an orthostatic interference (OI) disorder, meaning that its primary symptoms are lightheadedness or fainting due to an excessively reduced volume of blood returning to the heart when a person suffering from the condition stands up from a lying position. There are many disorders with OI as a primary symptom, but postural orthostatic tachycardia syndrome differs in that the fainting and lightheadedness are often accompanied by a rapid increase in heartbeat of up to 30 beats per minute, for a total of 120 beats per minute or more, within ten minutes of rising.
Doctors do not yet know the root cause of OI or its specific related disorders like postural orthostatic tachycardia syndrome, but the hypothesis is that it is a result in defects of either the sympathetic nervous system, the parasympathetic nervous system, or both.
There is no defined treatment for postural orthostatic tachycardia syndrome itself. Treatments instead focus on reducing the lowered blood volume through diet changes, avoiding alcohol, and other nutritional choices. Fainting can be avoided by some postural orthostatic tachycardia syndrome sufferers by sleeping with the head of the bed tilted up or by sleeping in a body stocking.
Postural orthostatic tachycardia syndrome sufferers often return to normal functionality, with about 80 percent of those with the condition living normal lives despite the condition. Often, postural orthostatic tachycardia syndrome follows a relapse-remission cycle that can last throughout someone's entire life. If experiencing fainting or lightheadedness when standing up, it could be important to visit a physician to see if postural orthostatic tachycardia syndrome or other OI disorders may be the root cause.