Postural orthostatic tachycardia syndrome (POTS) is a condition in which a change from lying to standing causes an abnormally large increase in heart rate. This occurs with symptoms that may include lightheadedness, trouble thinking, blurry vision, or weakness.
Medical Definition of Situational syncope Situational syncope: The temporary loss of consciousness in a particular kind of situation. The situations that trigger this reaction are diverse, and include having blood drawn, straining while urinating or defecating, and coughing.
Syncope is a temporary loss of consciousness usually related to insufficient blood flow to the brain. It’s also called fainting or "passing out.". It most often occurs when blood pressure is too low (hypotension) and the heart doesn't pump enough oxygen to the brain.