The interesting possibility of Apple’s HealthKit and the various other solutions isn’t the easy monitoring of data itself but the correlation of that with the rest of our lives already documented digitally.
Things like the intersection of blood pressure and heart rate to approximate stress levels cross referenced to your calendar and phone’s GPS - that’s the possibility of being able to look back at the past and see where the moments were that caused us stress or joy, the things that are most helping and hurting.
How much does checking your email actually quicken your pulse?
What was the impact of the second coffee that afternoon?
What will it mean to measure these things in a way that is much more accessible and actionable - thinking of it not as health or fitness or quantified self but as they way to listen to our bodies tell us about our commutes or jobs or interpersonal interactions or dietary habits or hobbies in a way we can’t as easily ignore.
Numbers and graphs and charts that are irrefutable.