POTS in a Nutshell...
Postural orthostatic tachycardia syndrome is a neurological condition (a form of dysautonomia) where the body does not control automatic functions properly - starting with heart rate and blood vessel constriction. For a more technical description, please visit Dysautonomia International's POTS page (a global non-profit that advocates on behalf of patients with autonomic nervous system disorders). I wanted to try to describe it here in simple terms for friends and family. One of my favorite articles to read that explains POTS in simple terms can be found here. POTS is not rare, affecting over 1 to 3 million Americans and an estimated 1 in 100 teens in some capacity. See pop up picture to the right. Also check out our blog post about the auto-immune aspects of POTS.
Think about your body's automatic functions - heart rate, blood pressure, digestion, sweating, sleeping, adrenaline release, among others. Your body is automatically controlling these functions. You don't think about your heart rate and blood pressure changing as you go about your day. Or your stomach digesting food after you eat. Or that you sweat as you get hot. Your body just does it. These functions are automatic and are controlled by your autonomic nervous system. When you have POTS, the signals that make these things happen are somehow interrupted.
When you lie down, stand up, or exercise, your body is constantly and automatically making adjustments to your heart rate and how hard blood vessels squeeze to move blood. Upon standing, your blood vessels have to squeeze harder to move blood from your feet to your head - which is harder for your body to do than when laying down. Unless you are doing heavy exercise, you probably don't even notice. This does not happen correctly when someone has POTS. Blood vessels are unable to squeeze hard enough when the patient stands up or when they exercise. This causes the heart to beat faster in an effort to move the blood upward or through-out the body. As this happens, the patient begins to experience dizziness, light headedness, and sometimes a release of adrenaline to compensate for the lack of blood flowing to the heart and brain. Even with all of this going on, the POTS patient looks fine on the outside - no one can see these changes. POTS patients often feel daily nausea, sporadic light headedness or dizziness, stomachaches, extreme hot and cold spells, anxiety caused from the racing heart and adrenaline release, fatigue and joint pain, sensitivity to flashing lights and many more symptoms.
To be diagnosed with POTS, the patient's heart rate must change 40 beats per minute for children and teens, and 30 beats per minute for adults within 10 minutes of standing. Patient symptoms vary from person to person but to have POTS, the heart rate change is the defining event. The other autonomic symptoms also occur and vary in intensity and number of symptoms. Simply having some occasional dizziness is probably not POTS. A diagnosis typically is done by a neurologist that has ordered a tilt table test that can detect failures in the autonomic nervous system including a sweat test. Some doctors may do a preliminary test called a poor man's tilt, done by lying down and finding heart rate and blood pressure upon standing at different intervals.
Click on the photos to the right to enlarge and read further.
Photo credits to www.dysautonomiainternational.org