I’ve been under the impression that Zwift rounds watt numbers to at least the closest 5 watt value. Might not account for the entire difference you’re seeing, but could be part of the issue.
If you’re in Zwift using ERG mode, you can raise or lower your bias by up to +/- 10%, which may help you get closer to the numbers you hope to see. (Might be able to adjust even if you’re not in ERG mode - can’t recall off the top of my head.)
Correct, once you’ve brought your historical data and done your test week, you’re good to go, as your thresholds are current and will be dynamically adjusted as you keep ticking off those workouts 
Good luck,
MJ
Thank you for reaching out!
Your AI Coach was referring to speed zones, not HR zones. Speed zones can be influenced by elevation changes and GPS accuracy, and we are actively working on improving this.
If you believe your HR zones are also incorrect, you can check them in the “Overview” tab. Our HR zone calculations may differ from Garmin’s, as we use a unique method to determine zone boundaries. You can adjust the Critical HR setting to see if that aligns them more closely with Garmin’s zones.
Regarding the AI Coach, we’re about to release improvements where aerobic workouts will be evaluated by HR instead of speed zones. In your case, this means it will no longer mention Z4 but may still flag time spent in Z3 when the workout was intended for Z1 and Z2. To improve compliance, we recommend:
I been noticing something similar. It seems there is workouts that are showing up on intervals.icu that are my usual workouts that I am used to. I had a 4800yd swim for tomorrow that I deleted. On my intervals I have a 2100 TEC. Other times Ill delete the session because of time constraints and will show again
Hi,
I came here to read about the pace issues with GPS. I’m looking to get some more information regarding this.
I’ve been on a few runs in the CBD where the gps pace can spike to 1:00min/k pace and I think it’s affecting my running pace profile and my recommended pace for workouts.
I did a 5k TT today.
How can I tell the 5k TT paces are being used for training zones and are these other runs with spiking speed affecting my zones?
I sometimes have these ROB (run off bike) sessions on days where I am not prescribed to bike. What kind of run is it expecting? Just that short run that it gives me, or does it expect me to have biked beforehand?
These runs may be associated with your availability constraints. It isn’t expecting a bike before, the logic is trying to keep you moving towards your goals within the limits you have given. The title of the workout doesn’t make sense, but follow the instructions (tempo). You could add a little bit warm up and cool down if you have time, for optimal workout.
OK sure that makes sense. Thanks for confirming!
Happy Training, fr0sty
Happy Training, fr0sty! 
I noticed that my race from last weekend is a blank in my calendar. Not a rest day, just blank:
It seems to be including the mileage in my weekly total, and I can see it on the iOS app, but in web for whatever reason it’s empty.
Hi. I think this may be a bug…my run performance chart doesn’t reflect my recent longer runs (90 min-ish) in the chart, and potentially in the calcs. Thanks!
reported thanks @wilcoxa35
Athletica keeps updating my bike heart rate zones with way too low heart rate numbers. I manually changed critical heart rate to 162 bpm last week as I tought this would be a better reflecion of my performance. After this weeks test week (FTP test and power profile test) it changed it again automatically.
Hi @Matthias … it should have updated to 180 bpm based on that test result. I’ve updated accordingly. I note that your settings are set at ‘ask me’ so if it reverts again please come back to this thread and I’ll create a bug report for this.
Thanks for your reply and for updating!
