I'm surprised to see that they apparently don't know that any wearable that uses optical sensors to measure heart rate can't measure HRV accurately. Optical se

I'm surprised to see that they apparently don't know that any wearable that uses optical sensors to measure heart rate can't measure HRV accurately. Optical sensors measure heart rate by averaging over time, which removes heart rate variability from the measurement. Also skin temperature is notoriously difficult to measure since it depends on how often a person bathes, whether they are perspiring, etc. I've never heard of a wearable that can measure core body temperature, wouldn't the sensor have to be placed inside the body? Most wearables use actigraphy to measure sleep, which means you have to tell it when sleep starts and ends, it can't tell the difference between watching TV and sleeping or detect when you take a nap. I seriously doubt you can get accurate respiration rate from a wearable also, especially when the person is moving around, unless they are wearing a chest strap, which most people find uncomfortable, especially if they have to wear it 24/7. I think they are way overestimating what wearables can do. There are some medical wearable patches that can do some of this, but they are generally really expensive and available via prescription only.