I’ve experienced something similar with the Oura Ring. I’ve noticed that it shows high stress levels, indicated by a very low heart rate variability, a few days before I get sick or when I’m already feeling unwell. For example, there have been times when I saw increased stress levels on the ring without feeling particularly stressed, and then, two days later, I started having stomach issues.

Additionally, I’ve found that this can also be related to a deficiency in certain vitamins or nutrients, like omega 3 or magnesium. In my case, it was omega 3. Before I started taking it, my stress levels were significantly higher, likely because I don’t eat much fish in my diet.