That's a scary title- I thought you were trying to tell if someone died!
From your last post, it looked like Stringify needs to have https only, not http. Did you find a way to get the Ardiuno to send https? I don't have one, but after reading your last post, I got curious and searched around on the internet about that, and it looked like https on an Arduino would be pretty complicated.
Regarding this flow, it would be similar to the flows used to turn a light off if a motion sensor doesn't see any motion for a certain time. Like the flows in this post:
If you don't get the heartbeat trigger, you would send an alert instead of turning off a light.
But if you try running any flow once a minute, or maybe even once every two minutes, and it goes all day, it will run into Stringify's limits and they will stop your flow.