Ted, you make a really astute observation. Given the variability of BP over the day, I would check at least twice (upon awakening and at least one other time) to get a general sense of your blood pressure. I wouldn't check immediately upon awakening, as it will typically give the lowest reading. On the other hand food such as breakfast (and caffeine!) can life our BP. Not to say anything about alcohol (hopefully not in the am), tobacco (hopefully not at all), and physical activity (hopefully regularly). And you just might to empty that bladder before you take it. So yes, you are spot on about variability (temporal and environmental stimuli-induced). THank you for your insights.