HR zones seem to be messed up after upgrade to 9.33

If you have the auto-detection of LTHR enabled, then the LTHR value (and hence the HRZ table too) might have been different during the activity than it is now.

silentvoyager said:

Another issue is that the sum of percentages in all zones is 96%. Isn't it supposed to be 100%?

Why do you think so? What about the time spent with HR below Z1?

My LTHR hasn't changed in a long time. It has been 162 for at least the last 6 months. And besides I wasn't running hard enough for LTHR to change. Also, when LTHR changes, the watch always notifies me about that and allows me to accept or reject the new value.

I think it is more of an issue with incorrect calculation. I think I know where those numbers come from. It calculates the top of Z4 using 98% and rounding down:

162 * 0.98 = 158.76, rounded down to 158.

Then it adds 1 to get the bottom of Z5.

But that is a flawed logic.

Also, who gave Garmin permission to change percentages of the zones to start with? My Z5 used to start at 162 or 100% of LTHR, and now it starts 3 beats lower. 

I'd tell there is some weird (and possibly buggy) algorithm for the auto-adjustments of the HR zones through some pseudo AI, messing the HRZ up over time. If you tap the bottom button "Reset Zones", the percentages will come back to the default 100-110% for Z5, 95-99% for Z4,etc...

Edit: better told, the percentages vary depending on the discipline - different percentages are used for the global HRZ, and different for each of the three disciplines (running, swimming, cycling). Personally, I removed all those discpline-specific profiles, and kept just the global settings, making it easier for me to monitor it.

Since both the %LTHR input and the calculated HR values are integers, some rounding is required. It is possible that only downward rounding is used for safety reasons.

Your Z4 ends with %LTHR 98%, resulting in HR = 162 * 98% = 158.8, which is rounded down to 158 bpm.

So Z5 starts with >158 bpm and the next integer in this case is 159 bpm.

I don't see that anything is wrong for this.

I think the main flaw in this logic is that Z4 ends at 98% and Z5 starts 99%. But then where the 98% to 99% gap between the zones goes? For most people that gap is going to be close to 2 bpm. 

With the current Garmin's implementation my Z5 actually starts at 98% because 159 divided by 162 is 0.981.

I think the way it should be is that Z4 should end at 99% too so there is no gap.

The way I'd implemented this is that I'd calculate the beginning of each zone based on the percentage and subtract one for the end of the previous zone. But subtracting percentages as Garmin does it is simply not mathematically correct. 

trux said:

If you tap the bottom button "Reset Zones", the percentages will come back to the default 100-110% for Z5, 95-99% for Z4,etc...

Apparently resetting zones still keeps the beginning of Z5 at 99%. I guess it is a new default according to Garmin. 

But in reality Garmin sets Z5 at 98% (rounded down) plus one, which is even less than 99%.

silentvoyager said:

Apparently resetting zones still keeps the beginning of Z5 at 99%.

Yes, the percentages in the HRZ tables differ for individual disciplines - they are different for Running than for Cycling, and different for Swimming too. And the global HRZ table is different again. It is probably based on some research, but personally I prefer having always the same zones for everything, hence I deleted all the HRZ tables for Sports, and kept only the global one, with the percentages 100-110% for Z5, 95-99% for Z4,etc.. Of course, you could also edit the percentages.

I had the same problem, als zones based on LTHR%. The watch did a autodetect of my max hr that was much to low, after that my zones where messed up, I have manually changed my max hr and turned of auto detect max hr