So it sounds like the saliva test shows up first, which is good. I'll have to see if I can train myself to recognize saliva density. Narrow pulse pressure is a sign of low blood volume. PP less than 25 is considered dangerously low, I believe. If water loading helps, but doesn't hold, you should look into whether you have low aldosterone. That is what Florinef replaces. Without the right amount of aldosterone, you can drink a lot, but you pee it all out. It doesn't stay in your blood. BP varies depending on time of day and your activities, so I'm not sure how much is gained by taking it at different times. Ideally, you should not take in caffeine or exercise 30 minutes before taking the measurement if you want baseline values to compare. If you haven't already done it, consider doing the Simple Test for Orthostatic Intolerance. Do NOT try this on your own. Have someone with you to take the readings and catch you in case you collapse. Remember to stand absolutely still during the test -- no wiggling anything. Make sure your assistant writes down symptoms, too. You can take the data from that test to your cardiologist to show BP and HR abnormalities with prolonged standing. Drat. Looks like you need a new meter. Yours is either erratic, or reading too low in which case you may have hypertension that needs to be dealt with. You might have orthostatic diastolic hypertension (see the link above) which is a form of OI. It's all kind of complicated and confusing (to me, anyway), but worth figuring out because treatment can often help us function better.