With the new Garmin Vivosmart 3 Activity Tracker that Garmin recently launched, Ray wrote in his review https://www.dcrainmaker.com/2017/04/garmin-vivosmart-3-activity-tracker-in-depth-review.html that the new stress status will come to F5 as well. Glad that Garmin is playing well here, remember Fuji when they introduce silent shutter many months after X-T1 release and gain a lot of kudos from customers who most (me included) became happy customers. Well done Garmin!
That would mean they managed HRV measurements with the optical sensor (similar to the HRV4Training app). Currently the stress test requires a chest strap. That would make this feature much more usable since I really can't t be bothered to stand around for three minutes with a chest strap early in the morning... ;)
