Postural orthostatic tachycardia syndrome (POTS)

https://en.wikipedia.org/wiki/Postural_orthostatic_tachycardia_syndrome

http://www.heartrhythmalliance.org/stars/uk/postural-tachycardia-syndrome-pots

Symptoms The main symptoms of POTS include: Syncope (fainting) Dizziness Light headedness Insomnia Palpitations (a sensation of heart pounding) Blurred vision Weakness Pooling or discolouration of the ankles or feet Chest pain Potentially related symptoms: Loss of concentration Migrainous headache Fatigue Shortness of breath Coldness of legs and fingers Body temperature regulation issues Hyperventilation (very fast breathing) that can further affect the control of blood pressure and increase the risk of fainting and feelings of anxiety