True, data can increase paranoia. It can have good effects also. One of the most common effects from wearing an activity tracker is people suddenly realize th

True, data can increase paranoia. It can have good effects also. One of the most common effects from wearing an activity tracker is people suddenly realize they are hardly moving at all. 95% of the time they are sitting (often 99% of the time). They thought they were an active person, but they only remember the active times, not the sitting times. Seeing the data can convince a person they need to move more. Maybe clinicians should recommend NOT using a tracker to people they see are hypochondriacs? (Better mental health evaluations should be a bigger part of medicine, though privacy is an issue.) Most people seem to use trackers for sports activity tracking. BP measurements throughout a day may actually have meaning, we just haven't done the research to know what that might be yet. There might be generalities, like a generally accepted "typical" peak BP value when working out in a gym or running. Or there may be things that are more specific that can be discovered, like BP should not peak and stay high for an hour after just standing up for a minute. We can probably answer some questions like what is the typical effect of a cup of coffee or a full meal on BP? Data inference can happen on mobile computers now, a smartwatch can tell when you are asleep without consulting a supercomputer. In the future these wearables will not report raw data, they will report inferences from algorithms. Figuring out those algorithms is just beginning.