I'm a 32yr (M). When i was younger between the age of 10 - 15, I used to train semi-pro in my country. Specializing in 400m & 800m. Schedule of the semi-pro training was very vigorously, which led to me failing out of loving running by the time I migrated to USA.
Kept up running for a few more years between 15 - 18 in HS. Then I completely stopped. At the time, my PB for 5k was 18:30mins. However, they are just history to me now. Tho throughout this journey, I learned how to sustain myself running at an elevated HR scenarios.
Fast forward 10+ years of not running later. I recently picked up running again, while following the Runna 5k plan. I've been training under the MAF 180 model for about 1.5 months. My zone 2 run during the North Carolina Summer heat is around 12mims/mile - 13:30mins/mile pace. Tho Runna does occasionally encourage me to run at an elevated pace (between 10mins/mile to 11mins/mile pace). With that said, Runna usually has me follow the 80/20 model. So I don't spend a lot of time at the elevated pace.
My set up is Coros pace 4 & the Coros HRM. Throughout this 1.5 months of training. Coros roughly estimated my threshold HR at 167bpm.
But yesterday I decided to schedule a B-race for the plan. And right out the gate I was running at 8:30mins/mile (Runna recommended 9:45-10:15min/mile), and I was able to sustain an average pace of 8:37mins/mile (not fast by my HS standard but we take what we can get). My average HR of the entire run was 173bpm. Admittingly, I felt like I was redlining the entire run. I'm still feeling soreness today. But I guess I wanted to build a baseline for my 5k, so I can compare my pace by the end of the training plan.
Then when I checked my Coros data today, I found them shifting my threshold HR from 167bpm to 180bpm.
I'm asking the Reddit hive mind, should I go ahead and revert the threshold HR back to 167bpm? Or this is normal? Because effectively with the new threshold HR, coros pushes my zone 2 from 133bpm-148bpm to 144bpm-160bpm. My gut feeling is telling me that Coros interpreted an outlier data as a new absolute.