I'm not sure the answer is just in applications. I think the application can work in partnership with new or existing technology. If a chip can be inserted so

I'm not sure the answer is just in applications. I think the application can work in partnership with new or existing technology. If a chip can be inserted somewhere in the human body and monitor are heart rate and function, glucose levels, caloric increase/decrease(whether we need to refuel the body), check our white/red blood cell counts, monitor genetic mutations for cancer, know when a virus has entered the body, or some of the other ideas expressed below. I believe this is the future, an application that works in concert with another device not just an application. Although there can be a suite of apps created for general purpose, very similar to "Cardiio" which is truly a genius application and is very, I mean very accurate. But to answer your question as to what app I would build. I would create a neuro technology app that monitors all activity of the brain, to record and know what gives us pleasure, know what makes us angry, happy, sad. What triggers emotion in us.