Aerobic or anaerobic zone? Look at the pictures!

I though I let you know the outcome of this. In the meantime I performed two Lactate tests and got a value of 141. I set the heart rate zones based on %LS and it now gives a max heart rate of 168, which maeks much more sense and is in line with my own plausibility checks.

So thank you very much, problem solved.

Great to hear!

The MaxHR in the heart rate zones is going to be set automatically though independently of what lactate threshold you set, it will be either set by the age formula in the absence of any other data, or if you reach a higher maxHR during a workout, it will automatically take that value. So what has happened probably is that in one of your runs you may have reached 168 at one point and the watch afterwards automatically corrected the maxHR using that value.

The maxHR value is not the maxHR you should not go over during exercise but rather the physical maximum HR you heart is able to reach.

I'm 46 and my maxHR according to the formula my maxHR should be 174, yet I have reached 188 doing interval training on the treadmill, and would probably go higher since I wasn't trying to reach the max and always stop when the time each of the interval lap finishes. And found the watch would correct the maxHR everytime I would reach a new high. Personally I don't care much of the maxHR since I use lactate threshold % as my heart zones.