Form has finally added heart-rate monitoring to its $200 augmented reality goggles that let athletic swimmers track their lap-swimming data.

Announced in September, the company has now updated its goggles in a partnership with Polar to measure a swimmer’s heart rate in real time. You have to buy both the goggles and the heart-rate sensors to make it work.

The Form Swim Goggles will incorporate the Polar heart-rate technology as an attachment, enabling a new level of training effectiveness and precision for swimmers.

The Form Swim Goggles are a pair of goggles with a see-through augmented-reality display that delivers performance metrics in real time. The Polar OH1 and OH1+ are optical heart-rate monitors that combine versatility, comfort, and simplicity. The Form Swim Goggles now support the Polar OH1 and OH1+ through a free software update from Form.

Above: Your view while swimming with Form/Polar.

Image Credit: Form

“Real-time heart rate is an essential aspect of training in land-based sports like running and cycling,” said Form CEO Dan Eisenhardt, in a statement. “Without that information, it’s easy to stagnate in your training, either by taking it too easy or by overtraining and burning out. Now, thanks to FORM and Polar, real-time heart rate has come to the pool. Swimmers can see their heart rate in our goggles’ display throughout their swim. This is a game-changer for swimmers, triathletes, and the coaches who train them.”

I tried these glasses out while swimming in Maui. I synced the goggles with an app on my iPhone and then pressed a button on the goggles to initiate a swim. Yellow pixels showed up on the screen indicating how far I had swum in yards. It also showed an estimate of calories burned. The numbers appeared on the screen in real time as I moved through the water.

If I were a competitive swimmer, I would know if I were on pace to beat my personal record. Form works best in lap pools, as opposed to swimming freely in the ocean.

By using the Form Swim Goggles in conjunction with either the Polar OH1 or OH1+, swimmers can see their heart rate in their line of sight throughout their swim, enabling them to precisely measure their effort in the moment — something that was previously impossible in the sport of swimming.

Above: Form’s heart-rate monitoring lets you analyze your swimming on an app.

Image Credit: Form

Completed swims will sync to the Form Swim App for iPhone and Android, which will match up heart-rate data to metrics like split times, stroke rate, stroke count, pace per 100, and calories in a single, easy-to-navigate view. Swimmers and coaches will gain greater insight into each swim, and they’ll be able to design future swim workouts with precision.

The Polar OH1/OH1+ attaches to the FORM Swim Goggles strap, where it will sit snugly against the swimmer’s temple, monitoring heart rate using its six-LED optical sensor and proprietary heart-rate algorithm.

The Form Swim Goggles are available now from Form. The Polar OH1 and OH1+ are available now from Polar and its authorized distributors and retailers.

Eisenhardt founded Form in Vancouver, Canada in 2016 after selling his previous company, Recon Instruments, to Intel in 2015. Finland-based Polar sells its products at 35,000 retailers in more than 80 countries. Existing Polar and Form customers can get a free Form mounting clip by visiting www.formswim.com/getyourclip.

“We’ve worked closely with Form over the past year to bring heart rate support to the Form Swim Goggles,” said Tom Fowler, president of Polar USA, in a statement. “We couldn’t be more pleased with the results. Swimming with the Form Swim Goggles and the Polar OH1/OH1+ combines the best of two worlds: the transformative training experience provided by Form and the gold standard in heart rate technology delivered by Polar.”