Postural orthostatic tachycardia syndrome (POTS, also called postural tachycardia syndrome) is a medical problem.  When a person has POTS, their heart beats faster than normal when they stand up.  POTS may also cause many other symptoms.

Meaning

 Postural means that POTS symptoms depend  on a person's posture (their position - for example, whether they are lying down or standing up)
 Orthostatic means that a person is standing up
 Tachycardia means that a person's heart is beating faster than normal
 A syndrome is a group of symptoms

Put together, the words "postural orthostatic tachycardia syndrome" mean that when a person stands up, they get tachycardia, and they also have other symptoms.

Signs and symptoms

When a healthy person stands up, their heart beats faster for a little while.  It does this to push blood to the brain.  Then the person's heart rate goes back to normal.

When a person with POTS stands up, their heart beats much faster than normal.  POTS is diagnosed when a person's heart rate increases by at least 30 beats per minute within 10 minutes after they stand up.  This is called postural tachycardia.

People with POTS also have other symptoms of orthostatic intolerance (symptoms that get worse when a person is standing up, and get better when the person is lying down).  These symptoms may include: 
 Palpitations (feeling the heart pounding)
 Feeling dizzy, fainting, or almost fainting
 Chest pain
 Trouble breathing, especially when exercising
 Feeling very weak or tired
 Blurred vision (not being able to see clearly)
 Headache
 Trouble concentrating or thinking
 Nausea
 Trouble sleeping
 Pallor (pale skin) or sweating

Symptoms may get worse if a person with POTS:
 Sits for a long time
 Stands for a long time
 Drinks alcohol or caffeine
 Gets too hot
 Exercises too much
 Eats a large meal

Causes
POTS can be caused by many different things.  Many of these causes are not well understood.

Some of the known causes of POTS include:
 Genetics
 Recently being sick with a virus
 Chronic diabetes
 Hypovolemia (not having enough blood in the body).  This causes less blood to get to the heart.  The body tries to fix this by making the heart beat faster, so more blood will get pushed into the heart.
 Problems with the nerves in the lower legs.  This causes blood to pool in the lower legs.  The body tries to fix this by making the heart beat faster so it can push more blood to the rest of the body.

POTS is more common in:
 Women between the ages of 15 and 50
 People who have recently been pregnant, had surgery, had a recent trauma, or had to rest in bed for a long time
 People who have had autoimmune diseases, irritable bowel syndrome, anemia, hyperthyroidism, fibromyalgia, amyloidosis, sarcoidosis, and cancer

Treatment 

There are many different treatments for the symptoms of POTS.  Some of these treatments include:
 Drinking a lot of water (this increases the amount of fluid in the body, which helps blood get to the heart more easily)
 Eating a high-salt diet (this helps keep fluid in the body and helps people with POTS from getting dehydrated)
 Getting exercise, especially exercise like recumbent bicycling (bicycling while lying back, which prevents symptoms caused by being upright)
 Using compression stockings (very tight socks) to keep blood from pooling in the legs
 Avoiding things that can make POTS worse, like getting dehydrated, exercising too much, eating large meals, drinking alcohol, or getting too hot 

No medications have been approved by the United States Food and Drug Administration to treat POTS.  However, sometimes doctors treat POTS with medications that:
 Prevent the body from losing salt;
 Raise blood pressure; and/or
 Keep the heart from pumping too fast.

Recovery 
Most people with POTS are able to get better with treatment.  About 6 out of every 10 people with POTS is able to recover within 5 years of being diagnosed with POTS.  About 9 out of every 10 people with POTS have some improvement with a combination of physical treatments and medicines. 

However, some people with POTS do not get better, and may even get worse over time.

Related pages
 Heart
 Heart rate
 Tachycardia
 Blood pressure

Other websites
 Postural Tachycardia Syndrome (POTS) - from the National Health Service of the United Kingdom (in simple English)
 Can POTS Be Cured?
 Postural Orthostatic Tachycardia Syndrome - from Dysautonomia International (includes detailed information about POTS, research, and finding doctors and support across the world)

References

Syndromes