Postural Orthostatic Tachycardia Syndrome also known as POTS is a type of dysautonomia.
This condition is characterized by a rise in heart rate of 30 beats or more per minute upon standing or a heart rate that exceeds 120 upon standing.

When a person stands gravity pulls their blood to their feet. A normal response to this will be a persons heart rate increasing a few beats a minute to help pull the blood up to the rest of your body.

In a person with POTS their blood pools in their feet depriving the rest of their body of much needed blood flow. The heart than increases its beats to help pull the blood from the feet.

Symptoms can vary from person to person but can effect your whole body things such as dizziness, nausea, gastrointestinal problems, extreme tiredness, and anxiety to name a few off a very long list. Some people only have a few of the things some people have them all.

Neurocardiogenic syncope is a sudden drop in blood pressure leading to fainting in reaction to stress. Basically anytime you become stressed even a bit beyond normal your body goes into shut down mode.

Both of these syndromes are often accompanied by other frustrating autoimmune and autonomic dysfunctions  many of which can not be seen. Leading many suffers plagued with the "but you don't look sick response" when inside they very much are sick.

Many of us are living everyday with something no one can see weighted on our backs. Whether  it is an "invisible" illness or a struggle in life. We are all trying our very best to get through each day with a smile on our faces.