@althaea35 thanks, I made it to help me avoid pushing too hard on my runs. My migraine doesn’t like too high effort and hr. Glad to see it’s useful for others!

@sky-runner On my Race S it triggers occasionally, but I agree that it needs an overhaul.

@surfboomerang looks similar

An new one this morning with a dive buddy in the beginning of the dive. After 10 seconds, the warning disapears.[image: 1781444377135-screenshot_20260614_123852_suunto.jpg]

It seems to happen when the watch is out of the phone’s bluetooth range for a while

@DonTomGot Do not know if this helps. But some suggestions from my side. Heap memory is tight on the watch and effectively unlimited in the simulator. I bumped into this several times. Two fixes I used: Use Uint8Array for HR data - up to 4000 samples seems to be OK Do not declare “scratch” variables in callbacks, make them global Yes, you will need to protect against undefined and null data, but I have only encountered this when starting an exercise. I think the problem you are seeing is probably memory related. Here are some things you could look for in the System Event Log from the watch. Log line Meaning ERR UI_FRAMEWORK : JS:0x...SyntaxError JS syntax error in a template ERR APPLICATION : Zapp:relMemCb (exec:ui) Memory pressure — release requested ERR APPLICATION : Zapp:RelMem→None avail Heap fully exhausted ERR DUKTAPE : JSalloc:16 JS engine can’t allocate — out of memory ERR WBMAIN Background worker error (often follows heap exhaustion) Second topic: when working on my AerobicGuide I was looking for the opposite type of algorithm, preserving spikes. I think the basic idea is to try to establish a slower-moving baseline and then look at rapid deviations from that. You can probably find something in Python that you can play with. Then it becomes a question of picking a simple enough algorithm that it can be implemented on the watch.