There are virtually no smartwatches nowadays that aren't equipped with an optical sensor for measuring your heart rate. Heart rate combined with speed - which can be easily determined using GPS - is a fairly detailed measure of performance, for example, when running or cycling. In our experience, wrist-based heart rate measurement generally works very well, but sudden and relatively significant changes in heart rate can result in slow or delayed readings. This primarily affects ambitious runners and other intense athletes who can push themselves (almost) to their limits and want to do so as part of a training program.
Garmin has such athletes in mind with the HRM 600. This is a heart rate monitor that measures not only heart rate but also heart rate variability, analyzing not only heart rate per time interval, but also the temporal deviation of individual heart rate beats from one another. Advanced metrics for running efficiency are also on board (Running Dynamics) - in combination with a compatible smartwatch. Step Speed Loss, which measures the loss of speed through ground contact, is only possible with the brand-new Forerunner 970. Runners should, of course, try to minimize this value by optimizing their running style. But stride length, ground contact time and vertical movement can be analyzed with other models than just the Forerunner 970.
The HRM 600 strap can also be used without a smartwatch, which could be useful for boxing or other martial arts, or even climbing. The rechargeable battery is advertised as having a battery life of up to two months.
The model is listed for $169.99 and will be available to order from May 21.