What doesn’t kill you makes you stronger, you could eventually adapt.
I’ve had the pleasure of experiencing pepper spray in training and witnessed many exposures. People have different tolerances, some will be instantly incapacitated, while others seem mildly irritated. Most people fall in the middle. I’ve never known someone to build up such an intolerance that it doesn’t affect them, however they’re ability to function seems to increase with each exposure. For instance, person A has a low tolerance. They gets pepper sprayed, and can’t see, can’t breathe, can’t do anything but stick their head in a bucket and snot all over themselves.
Next time Person A gets sprayed, they can run through a obstacle course, drag a dummy, etc… before they stick their head in a bucket and snot all over themselves. For what its worth, most people can go through the course the first time, however they will still improve after their first exposure. I’m sure this is in part due to the reduced stress of knowing what to expect, however it seems recovery times also shorten.
Also, strictly observational - I’ve noticed pepper spray seems to effect the fair skinned and women more. Not sure why. I’ve been pepper sprayed twice, and each time, I was just a little puffy-eyed 30 minutes after exposure, and after an hour or two there was no difference in my appearance. I’ve observed fair skinned people’s face actually swell with blood shot eyes that lasted for a day or two.
Also, there are plenty of designer hot sauces on the market that are hotter than pepper spray:
I was introduced to them by a coworker, as he loved them. Put them on everything, leading me to believe his taste buds must have been burned off years ago. Oddly enough, he was fair skinned, and swelled up like a balloon when he got sprayed. He did seem to feel the effects for less time through, probably because he was just used to dealing with the burn.