Honest question:
If you felt just fine but your watch said you were seriously stressed out, would you worry?
And the other way … if you were having the worst day you could remember but your watch said you were stress-free, would that make you feel better?
The Apple Watch and similar gadgets are great at direct objective measurements like heart rate. They do well enough, but with notable shortcomings, at indirect objective measurements such as VO2 max. (For example, the calculation clearly doesn’t account for ambient temperature … and you will get radically different figures exercising outdoors in Arizona in summer and winter.)
But subjective measurements, such as how you’re feeling?
I’m at an utter loss as to why you’d need a machine to tell you something like that, or what you’d do with the information.
b&