Need help with a simple procedure

I'm creating a mod that detects if you are in hot or cold areas and displays an overlay if you are... well I have the overlay popup when you are in these areas but only if the player does something like (pulls up inventory, etc.) I want it to constantly update. I used the repeat for infinity block but that lagged and won't let me open the world. I've tried player and world tick updates but that only updates if I do something like pulling up my inventory or any other GUI. Any help or suggestions would be appreciated, hopefully this won't be a complicated fix.