My Oura Ring warned me something was wrong - I didn't listen (and quickly regretted it)

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ZDNET's key takeaways 

• The Oura Ring detected my cold early. 
• Health trackers are getting good at this. 
• It's a helpful illness detector and a way to check in when sick. 

Last Wednesday morning, I woke up and did what I normally do when I open my eyes. I grabbed my phone and checked my Oura app to see how I slept. This morning, however, Oura's home page looked a bit different. 

Unlike the sleep and readiness scores I usually see on the home page, a new message appeared on top. While no biomarker deviated strongly from my baseline, Oura's Symptom Radar feature warned me that my biometrics indicated "major signs of strain." It encouraged me to take it easy -- a tall task given that I was headed into the office for the workday ...