In an attempt to get a specialist referral for what I thought was POTS, I did a 30-minutes poor man's tilt test (i.e. lay down for 20 mins, took my HR and then stood up). My laying-down HR was 73 bpm. By 10 mins, it was 92. It kept going up and was 106 at 30 minutes. According to the POTS criteria, your HR has to go up 30bpm above baseline within 10 minutes and mine didn't. On the other hand, is it normal for it just to keep going up and up? It was 35 bpm above baseline after 30 minutes. I don't feel dizzy on standing but I do find sitting and standing difficult and have to lie down for 15 minutes in every hour because I get exhausted, even if I'm just sitting with my feet up. I find standing more tiring than walking, a classic OI symptom. POTS? And if not, is that heart rate pattern remotely normal?