The above is the day after a 2 hour ride, pushing myself but not full on. I was not feeling stressed, indeed just taking it easy and chilling out reading etc. My usual daily stress average is around 35. I'm assuming (hoping!) the stress measured is to be expected and (due to) recovery.
Btw, the blank period is my watch (Vivosmart 5) recharging. You'll see.I sleep well too!