That does not mean you don't have it. When I had mine my blood pressure stayed the same as well as my heart rate it was then when they gave me nitroglycerin and tilted me up that I went unconscious and the doctor told me my heart rate spiked and then my blood pressure dropped and then my heart rate dropped. He diagnosed me as Vasovagal Syncope which according to him is a form of POTS. Also went into Atrial Fibrillation when I came back too, talk about scary stuff. I am a 35 y/o male.