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Circuit Breaker

MOOV HR measures heart rate from the head for better accuracy

There’s too much tissue at the wrist to get an accurate reading

Courtesy of MOOV

Tracking steps is no longer enough. Now it's all about measuring intensity and heart rate, but unfortunately wrist-based wearables are not very accurate. The MOOV HR promises heart rate monitoring comparable to that of the electrocardiogram (EKG) — the gold standard of heart measurement — by measuring from the forehead instead.

Older versions of the MOOV were worn around the ankle or the wrist. MOOV HR is a sensor in either a forehead sweatband (for most activities) or swim cap. The device, unlike Fitbit or Jawbone, works more like an AI coach than a fitness tracker. The main sell is that you can pick a workout from the app and get real-time feedback on how you’re performing. When synced with the app, HR will show heart rate data both in the beats-per-minute number and as a continuous wave.

Most wearables monitor heart rate using LED lights embedded in the device. The lights reflect on the skin to detect the pulse and changes in blood volume; this is turned into the heart rate number. Watches are convenient, but studies have suggested that the wrist is not a good place for taking accurate measurements.

“On the wrist there are so many layers of tissue, so when the heart pumps the blood to the area, the signal is noisy,” says MOOV co-founder Nikola Hu. In contrast, he says, the skin at the temples is much thinner, so it creates a much clearer signal that can be picked up by the sensor in the sweatband or swim cap.

A sweatband should also be more accurate because it’s in constant contact with the skin. Depending on how tightly you wear a wrist tracker, it can slip up and down when you move your arms. Any gap between the sensor and the skin can cause inaccuracy. (According to researchers, this is one reason accuracy goes down when people work out harder; most people move their arms more as intensity increases.) There’s no gap in a sensor attached to a sweatband.

MOOV isn’t the only company moving away from wrist-based heart rate monitoring. Companies like Jabra and Bragi are creating earbuds that have sensors, though Hu noted that he thought a sweatband would be more practical. It’s theoretically possible to be very accurate by measuring the thin skin on the fingertips, for example, but good measurement needed to be balanced with convenience, he adds.

The MOOV HR is part of a wave of wearables that are moving away from simply counting steps. “To have a really good, effective workout we need to get to a certain intensity—just walking steps or staying in a very low heart-rate zone is not really going to help if I want to lose weight or improve my cardiovascular health,” says Meng Li, another MOOV co-founder. Of course, researchers suggest that both are important: steady movement for overall health, and intense workouts to increase cardiovascular fitness.

The team tested the new gadget on about 20 people at the Human Performance Lab at the University of California-San Francisco. They declined to share detailed results, but say that the results showed comparable accuracy to an EKG. The tests followed the lab’s testing procedure, which measures movement when seated in the chair, doing one-minute intervals, and then progressively running faster on the treadmill. They also tested the accuracy against an EKG for boxing, because one of their programs is a boxing program.

The MOOV HR is available for $59.95 for either sweatband or swim cap, or $99 for both during the launch.