Fitbit Air - One Month Of Scientific Testing!
In a Nutshell
The Fitbit Air delivers excellent heart rate tracking (0.99-1.00 correlation) when worn on the biceps versus good wrist performance (0.92-0.99), excelling particularly during outdoor cycling and weightlifting where wrist readings often miss peaks. It ranks among the top devices for sleep stage tracking with 73-85% agreement across stages and earns "great" to "perfect" overall scores. At $99, it's positioned as the cheapest option for high-quality raw data and sleep tracking, with third-party biceps bands expected soon on Amazon.
These notes were generated by AI and may contain inaccuracies.
The Fitbit Air has been flying off the shelves the last few months and there's good reason for this. It's a really good tracker at a very affordable price. Data has been collected over the last month using this device, both on the wrist and on the biceps. The analysis focuses on data and data science to evaluate device performance by comparing it to reference devices.
Indoor cycling was tested as one of the easiest exercises for heart rate tracking devices. The Polar H10 ECG chest strap served as the reference device, using ECG electrical signals of the heart for accurate measurement. When worn on the wrist, the Fitbit Air showed a correlation value of 0.99 with the reference device. When worn on the biceps, the correlation value reached 1.00, which is perfect correlation that cannot be higher than one. Individual spinning sessions showed the Fitbit Air on the wrist performing quite well with only minor moments of deviation, while the biceps position delivered basically perfect tracking.
A biceps band was created for optimal performance, as commercial versions are expected to become available on Amazon within a few months. One available biceps band was spotted on AliExpress, though quality remains uncertain.
For running, the Fitbit Air performed quite well on the wrist with a correlation of 0.99. On the biceps, performance was even better with points closer to the reference line, though the correlation remained at least rounded 0.99. Individual running sessions showed similar overall patterns, though some small details like full heart rate dips were occasionally missed on the wrist but detected on the biceps. The improvement from wrist to biceps was smaller compared to other exercises.
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