There's a new accessory available for owners of iOS devices who are looking to stay healthy and improve their tolerance to stress. While there are iOS-connected scales and blood pressure cuffs, until now nobody has looked at cardiorespiratory fitness and stress levels. That's where the new Tinké (US$119, pronounced "tink") comes into play.
The tiny sensor, available in black, blue, pink and white, uses optical sensing technologies to capture blood volume changes. With the touch of a thumb to a pair of tiny windows on the device, the Tinké app (free) calculates a pair of indexes. The Vita index is "a personalized cardiorespiratory score that is created by piecing data collected from heart rate, blood oxygen level and respiratory rate. The Zen index measures heart rate variability to determine a number that provides a relative reading of your stress.
How it works
Tinké is a tiny sensor that plugs right into an iOS device with a 30-pin Dock connector, and also works well with the Lightning to 30-pin adaptor on newer devices. There's a tiny cover that pops off of the top, keeping the connector protected when Tinké is not being used. That cover clicks into place on the bottom of the Tinké while you're using the device so you don't misplace it -- a nice little design feature. Plugging in the Tinké launches the app, and you're then prompted to place your thumb over the two "windows" and maintain a constant pressure. Both red light and infrared are used to take the readings.
Each index takes about a minute to measure and calculate. For the Vita Index, your heart rate, respiratory rate and blood oxygen levels are measured. A lower resting heart rate is a good indicator of cardiorespiratory health, as is a respiratory rate of between 10 and 20 breaths per minute. The blood oxygen level looks for a 95 percent or better saturation as a healthy measurement.
The Zen Index takes you through a 60-second controlled breathing exercise. There are five different circles indicating breathing rates from slow to fast, and you pick one that feels about right for you, trying to match your breaths to the expansion and contraction of the circle on the display. The idea seems to be that by practicing the controlled breathing with Tinké, you'll later be able to achieve that same breath control in stressful situations where you don't have the device at hand.
Everything is social these days, so you can share ("shout") your results with friends through a Tinké network or Facebook. If you'd rather not have your friends and relatives know about your health and well-being, you can also keep your results private. There are also achievement badges that motivate you to keep making regular measurements. What you want to do is make sure that both indexes climb to a higher level over time, or at least remain steady if you're already at a high level of cardiorespiratory health. Although it wasn't available at the time I was testing Tinké, there will be a "world" index so you can see how your Vita and Zen indexes compare with the average of the rest of the Tinké users.
Tinké in use
The Tinké is surprisingly easy to use, so much so that I found myself taking measurements multiple times per day. There's no battery to worry about charging as the Tinké is powered by your iOS device, and there's nothing really difficult about the setup process.
The Tinké app is in its first iteration and might need a little work. I found the font used on many screens to be difficult to read, and the developers seem to have a penchant for putting light colors on light backgrounds. In addition, I don't believe that the app is optimized for the iPhone 5, as I ran into several situations where text was cut off near the bottom of the screen.
I also wasn't a fan of the app UI -- when you tap on one of the four buttons at the bottom of the screen (achievements and history, Vita Index, Zen Index and Sharing), multiple colored stripes pop up from the bottom, each one being a menu selection. Take your finger off of that button for a second and the menu disappears. A persistent menu that stays available until you make a choice may not be as artistic, but would certainly be much easier to use.