Heart rate drift without power meter

1

Hello, I am wondering how I can manually input heart rate drift as I train without a power meter.

The reason for this is on a Z2 ride I keep HR below 140 but it can drift up to 150 especially on longer rides and hotter days. Then the website will put me into Z3, producing incorrect fatigue and fitness numbers. For example, as I get better at Z2 and see less drift, the website will mark this as decreasing training load.

So I’m wondering if there is a way to manually change the latter portion of my rides, which the website marks as Z3 to Z2 and then let the website recognize it as HR drift. Or maybe just manually change the zone to correct the fatigue scores? Or maybe I should just extend my rides as I get fitter and aim for the same amount of HR drift so I get consistent scores. Any input would be appreciated.

2

How can you know if there’s drift? And how much?
You need both HR and Power to evaluate drift.

You say you keep HR below 140 but it can go up to 150. Not understanding what you mean.
How do you know it’s drift and not higher intensity?

If HR goes up above the top of Z2, then you are in Z3 (HR zone), no matter if it is caused by drift or not. If you had power, it could still be Z2 power, but it could just as well be Z3 or Z1 power depending on the situation.