Self quantification of health and fitness.

The number of physiological parameters that can currently be selfmonitored by individuals is extensive and rapidly increasing. Miniaturization and cost reduction of sensors, such as accelerometers and altimeters, have made it easily possible to track patterns of exertion, rest, and sleep. The patient assured me that, although he had never experienced any symptoms, he was sure that there was something wrong with his heart. When I inquired how he could be certain, he informed me that he had been recording his heart ate and rhythm automatically for some time on a smartphone application. Recently, for he first time, he recorded a heart rate that fluctuated between 130 to 150 beats/min and ersisted for almost 1 hour before returning to his usual rate of 60 beats/min. This was ccompanied by an increase in his smartphone app quantified stress level, but was unreated to his sleep pattern, exercise level, or dietary and caloric intake that he also moniored and recorded daily. And so was the concept of self quantification of health and tness injected into my medical practice. My introduction to the concept of self quantification came from Chris Anderson, the ditor of Wired® magazine, during a JACC Editorial Board retreat. He pointed out that he development of small physiological sensors had made it possible for almost anyone o monitor a variety of their own health and fitness parameters. My impression was that hris represented a very small group in the San Francisco Bay area with an extreme inerest in their own wellness who did such monitoring. In fact, the majority of questions hat he received from the Board related to why he did this and what he did with the ata. Although a movement called “Quantified Self” did indeed begin in San Francisco, t has now spread throughout the United States through a spectrum of blogs, local eetings, and large conferences, and attracted considerable attention. An article in the conomist (1) describes Quantified Self as (my translation) an eclectic mix of early dopters, fitness zealots, technology enthusiasts, personal-development devotees, and paients sharing a belief that self-tracking, or gathering and analyzing data about their veryday activities, can help them improve their lives. The number of physiological parameters that can currently be self-monitored by indiiduals is extensive and rapidly increasing. Miniaturization and cost reduction of sensors, uch as accelerometers and altimeters, have made it easily possible to track patterns of xertion, rest, and sleep. Devices to record heart rate variability and skin conduction can rovide indirect evidence of the level of stress. The Zeo® is a headband that records and nalyzes brainwaves to determine the duration and level (e.g., rapid eye movement) of leep. A sensor exists that can be attached to an inhaler used by asthmatics to determine he influence of environment on their condition. Highly motivated individuals can have heir DNA sequenced for disease risk by services such as 23andMe, and can obtain lood and stool analysis performed by services such as Your Future Health. Moreover evices used for these purposes can be easily incorporated into Smartphones or bracelets, nd can be readily interfaced to computers and the Internet. Accordingly, people can not nly track their own characteristics, but also enter them into a database to compare hem to others who are using the same technology. The implications of such databases or individuals as well as medicine in general are obvious.