Still trying to workout this one but there’s a massive difference (up to 10 beats) between the zones on my Garmin and a Wattbike that I use, they are linked together.
For example my zone 4 according to Garmin is 159-172 and on the Wattbike it’s 152-164.
Why the difference ? should I just take an average of both?
I like my science and my facts and figures etc so like to make sure I’m working at the correct level for the session I’m doing.
Anyone help

What are the zones based on? Are they based on LTHR or max heart rate?

Could be the difference?

There seem to be several methods for calculating HR zones, could be Garmin and Wattbike use different ones?

They are based on max heart rate via Garmin, not sure on the wattbike, you could be right though….