Yes, the watch automatically measures heart rate variability (HRV) during sleep. These values are used in the "Nightly Recharge" function. However, manual HRV measurement is not possible.

The watch can measure heart rate, but there is no specific information on whether it also measures heart rate variability (HRV). Heart rate measurement is one of the health functions listed in the watch's features. If you need specific information on HRV measurement, I recommend contacting the official documentation or the manufacturer.