It varies amazingly from person to person and for me it can vary from day to day.
Some days I can eat chillies raw and not really notice. I've been into restaurants and been warned that the dish I'm ordering is very hot and spicy or the hottest on their menu, and yet it wasn't for either of us, but on other days, I can't even eat a polo (mint), tictac or peppermint mentos, or go near anything even mildly chilli related.
For me, the cause is my brittle asthma. Sometimes even peppermint toothpaste on the electric toothbrush is too much for my asthma. And there's no warning, I'm either totally fine and can eat chillies raw or the slightest hint of them can trigger an asthma attack. We're going through one of those "phases" at the moment. No mint flavoured anything, though curiously in with actual mint grown in my garden (go figure), manual tooth brush, certainly no chillies, no hot paprika, and no pickled chillies. Next week I might be fine again but tonight it's back to double antihistamine tablets and extra asthma medication just to sleep, so nothing spicy on the chilli front.