To me, Emfit makes a lot more sense as these measurements (including heart rate variability) are best made when you are relaxed and sleeping. It's a sensor that

To me, Emfit makes a lot more sense as these measurements (including heart rate variability) are best made when you are relaxed and sleeping. It's a sensor that is put under the mattress. It will detect when you lie down and continuously collect ballistocardiography and sleep data: https://www.emfit.com https://www.emfit.com During the day, you can wear a smartwatch or a smart ring instead.