Train Like the Elites with New Lactate Threshold Tracker

Lactate Threshold Tracker

For an athlete looking to set a new PR, there’s nothing cooler than visiting a real performance lab to get a feel for how your training is going. Sure, you may feel a bit like a guinea pig, even subjecting yourself to blood draws mid-treadmill session. But you’ll learn far more about your fitness than you could from the average tracker…until now.

BSX Insight, a new wearable device with an expected release date of December 15, is designed to determine your lactate threshold using a simple at-home gadget. Translation: It will tell you the exercise intensity at which your body can no longer rid itself of the acid produced by hard-working muscles. “Your lactate threshold is a snapshot of your current fitness level,” BSX Insight founder Dr. Dustin Freckleton says.

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Tracking Lactate Threshold Outside the Lab

Lactate Threshold Tracker

Freckleton, a marathoner and triathlete, was in med school when he set out to develop a data-driven way to plan his workouts. He wanted them to be both efficient — and as challenging as possible. “I was looking for that biosignal hack: The single most important thing to measure and track,” Freckleton says. “As the research progressed, it became clear that was lactate threshold. It’s the gold standard technique.”

The only problem: The best way to determine lactate threshold was to go into a performance lab. For $200 or more, you’d undergo a treadmill test during which blood would be drawn from your finger or earlobe every few minutes for the duration of the test (usually around 30 to 45 minutes). If that sounds unpleasant, it’s because it is.

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Eventually, Freckleton found a better way. BSX Insight is a tiny tracker fitted on a compression sleeve worn on an athlete’s calf. Using LED light technology, the gadget looks inside the wearer’s muscles, picking up various markers of lactate threshold during a workout. In tests comparing the two methods side to side, BSX Insight offered nearly identical results compared to traditional blood-based lactate threshold tests. While pricey, the trackers are still more affordable than multiple trips to a performance lab — with devices for cycling, running and multisport athletes ranging from $299.99 to $419.99.

Worn in tandem with a heart rate monitor, BSX Insight will wirelessly upload your results to its still-in-development iOS app after your test is complete. Then, it breaks down your results into distinct heart rate-based training zones. In other words, for cyclists or runners using a zone-based training plan, they’ll now know exactly how hard to push their heart rate during easy and hard workouts. “Instead of saying, “I’m going to train for 90 minutes at an easy pace, or I’m supposed to do eight repeats at high intensity, you can know that during the course of this workout, you need to be between 180 and 186 beats per minute the entire time, or 200 to 215 wattage on a bike,” Freckleton says.

Lactate Threshold Tracker

Lactate Threshold Training: The Key to Smarter Racing?

Intense athletes often strive to exercise at or beyond their lactate threshold, so that their bodies can learn to efficiently clear out out the acid byproducts of a hard workout. This enables them to push themselves harder, longer and faster as they continue to train. Freckleton says he was able to dramatically improve his times using the tracker — and testimonials on the company’s blog show other athletes have seen results, too.

The device can be used for two different purposes: One is to continuously monitor your lactate threshold, in order to see how it changes over time. Freckleton recommends users do this performance benchmarking every six to eight weeks.

Athletes can also wear the tracker to analyze muscle oxygenation during each workout. This measures how stressful various routines are on your body and how fast your muscles recover afterwards. “Knowing what that recovery pattern looks like, you can know how long to rest or how hard to push yourself,” Freckleton says.

To be clear, someone training for their first 5K might not need a device like this. But Freckleton says its perfect for lifelong competitive athletes looking to place in their age group, or set a new personal best. Unlike other trackers, which will tell you steps taken, miles logged or heart rate achieved after a workout, BSX Insight tells you how to plan your workouts before they start. “You can’t make good driving decisions looking backwards, you’ve got to look forward,” Freckleton says.

To learn more about BSX Insight, or to pre-order a device, visit

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