Wild new wearable shines a light through your skin to measure lactate threshold

In case you haven’t noticed, wearable tech is entering a new era. Now that we’re past that initial surge of accelerometer-equipped wristbands, many companies have started thinking beyond simple wrist-borne activity tracking.
Case in point: the BSXinsight. Designed to fit inside a compression sock, this sensor-packed device can record a wide range of different fitness metrics, including heart rate, cadence, pace, calories burned, and lactate threshold.
That last one — your lactate threshold — is that moment during a workout where your body can’t flush lactic acid out of your bloodstream faster than it is being produced. Turns out it’s an extremely useful measurement of exercise intensity for training and racing in endurance sports — and the
BSXinsight just so happens to be the first and, so far, the only wearable device that can measure it.

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To gather this data, the device is first attached to the user’s calf by slipping it into the carrying pocket of a compression sock. It then periodically shines a low-power LED into your skin to analyze the composition of the underlying muscle. Using the right algorithms and a sensor that can detect minute changes in light, the device can tell you exactly how much lactic acid is in your muscle tissue at any given moment.
The BSXinsight, in other words, looks inside your body while you’re exercising to measure biological signals and determine how hard your muscles are working. This data, when analyzed alongside performance data picked up by its other sensors, allows BSXinsight to optimize your workout in real time. It can tell you whether to speed up, slow down, or, when necessary, rest — so that you’re never working harder than you need to be.
BSX wrapped up a successful Kickstarter campaign for the device roughly a year ago, and the device is now available for purchase on the company’s website. Stay tuned for our hands-on review.