Cardiio has launched their first, much anticipated, biosensor that uses an iPhone or iPad camera to provide touch free heart rate measurements and related health predictions.

The app, priced at $4.99, is beautiful, intuitive, and claims to accurately assess resting heart rate to within three beats per minute of standard medical pulse monitors.

Cardiio and its PhD Co-Founders Ming-Zher Poh and Yukkee Poh spun out of the Massachusetts Institute of Technology (MIT) Media Lab, where the core technology was developed and published in multiple peer reviewed journals (see here, here, and here). Cardiio is also a recent graduate of the digital health acceleator Rock Health.

While Cardiio’s technology is based on validated, cutting edge research–the application itself is deceptively simple and elegant to use. You literally place your face within a red circle on a stethoscope image, enjoy a few seconds of quotes celebrating science or childhood rhymes, and then receive your heart rate reading.

With every heartbeat, blood rushes to the vessels of the face. Per the team’s research at MIT, this increase in blood volume absorbs more light, which results in a corresponding decrease in the light reflected from the face. Cloud-based software tracks this variance and calculates the heart rate.

The “Insight” screen lists your most recent heart rate, today’s high and low readings, and your daily, weekly, and monthly average. Simple visuals demonstrate today’s fitness level, life expectancy, and how you stack up next to the average person. If you are having a particularly stressful day and your heart rate is elevated, seeing your life expectancy next to a hamster or crocodile is a nice touch.

The app currently works only on the front (ie screen-side) camera of dual core iOS devices including the iPhone 4S, iPad2, and above.

Cardiio makes a few recommendations for accurate readings, including using the application in a well lit but not backlit area, holding the phone/iPad in front of you rather than looking down, and holding the phone/iPad as still as possible.

The app only works for resting heart rate–beware using it when particularly stressed or after climbing a few flights of stairs if you want to protect the accuracy of your accrued average reading. (There was a cute moment on Rock Health Demo Day when a nervous Yukkee had a through the roof heart rate reading during their demonstration).

Its not currently possible to delete results that the user believes are inaccurate or that were taken when not at rest, or note other important variables when the measurement was taken to fully support self quantification. The application also does not support multiple users, a point of frustration in households where there may be only one SmartPhone, or parents wanting to measure their child’s heart rate.

I also could not find information clarifying that Cardiio’s fitness and life expectancy predictions are based on the average adult until you manually enter your age and sex in another part of the app, which may worry parents who use the app on young children, such as a three year old with a normal pulse of up to 110 beats per minute. The life expectancy calculator also does not take into consideration medical co-morbidities or drugs that may affect heart rate and the accuracy of Cardiio’s predictions, such as individuals on a Beta blocker, or with thyroid disease.

These limitations represent areas of improvement for future releases, but as an initial offering the application remains impressive.

While its not clear how popular regularly measuring ones heart rate will be in the general population, this certainly will be a tool eagerly taken up by self quantifiers. I am most excited about the utility of this for passive, no touch monitoring in health care  settings as the technology advances to not require the camera so perfectly aligned and close to the face. There is also significant applicability in the gaming and fitness industries.

Cardiio meets and exceeds what is the often overpromised but underachieved potential of digital health; yes the app is well designed and engaging, but its also built upon validated technology, and has potential clinical and personal utility at many points along the spectrum of the well to severely ill.