COR Evidence

What COR members' own data shows.

Every reading COR members choose to tag or note adds to a growing picture of how everyday life shows up in inflammation. When a pattern is strong enough — enough members, and clearly beyond chance — we publish it here. Each finding compares members with their own usual readings, so it is about change within a person, not one person against another.

Finding 001 · October 2026

A cold shows up in your inflammation — and lingers

When COR members logged a cold, flu or COVID, their ESR ran a median 33% above their own baseline. In 43% of illness episodes it reached 1.5 times baseline or more.

It often stayed up after people felt better. Readings noted as “recovered” were, if anything, higher than readings taken while still sick (a median 1.56 times baseline, against 1.29 times). That fits how inflammation works: it can lag behind symptoms. A few COVID cases took several weeks to return to baseline.

What this means for you

  • Don't set or judge your baseline while you're sick or just after.
  • Tag illness on your check-ins so you can see it in your trend.
  • One high reading during or after an illness isn't cause for alarm on its own. Readings that stay high are worth discussing with your doctor.

How we looked

We reviewed 6,635 valid tests from 1,195 COR members. Members had written a note or tag about an illness on 102 tests, which grouped into 67 illness episodes where the member had enough other readings to establish a personal baseline. Each episode was compared with that member's own usual ESR.

The limits

This is observational, self-reported data, not a controlled study. Members chose whether to note an illness, subgroups are small, and it can't predict how much any one illness will move any one person's number.

How a finding gets published

Every month we re-check every pattern in members' notes and tags. A pattern becomes COR Evidence only when at least 20 members contribute, significantly more of them move one way than the other, and the pattern stands out from the general tendency to note readings that look unusual. Plenty of patterns we've looked at — sugar, alcohol, fasting, sleep, exercise — don't clear that bar yet. As more members tag their check-ins, some will.

Every tag helps. If you're a member, tagging what's going on (a cold, a late night, a big workout) builds your own picture and the next finding. Not a member yet? See how the COR One works.

General information, not medical advice. Discuss your results with your healthcare professional.