Think I missed the mention of wrist cuff, because I had in my mind the upper arm variety.
What if the objective symptoms wind up pointing toward P.O.T.S.?
By definition, if you have no symptoms, you can rule out POTS-hyperadrenergic or otherwise. What does your doctor say about your blood pressure? The information Living In Hope requested above would give a better picture of what might be going on. All wrist cuffs that i've seen instruct you to hold the arm to your chest during the reading, so having your arm in other positions will likely give inaccurate results. Read the instructions for your cuff carefully to obtain a correct reading.
What was your pulse doing with standing versus lying down?
I believe your arm should not be hanging straight down when you take it standing, though it shouldn't necessarily have to be clear up at shoulder height. You might try resting the lower part of your arm on the kitchen counter (maybe use a thick book on top of the counter if it is down too far for your height) without leaning and see what happens?
Some people when they have orthostatic intolerance actually have a hyperadrenergic reaction to standing to prevent passing out, where the body overcompensates. I've had my blood pressure go up with standing with my P.O.T.S. (postural orthostatic tachycardia syndrome). My pulse also goes up.
Please remeasure lying down and standing, if you would, and list your pulses as well? I'm interested to know what your pulse is doing. You might even take your pulse just one minute after being in a standing position and let me know that number also?