but, it DOES happen instantly. Yes, it lingers, but it starts immediately.Niether do I but in my experience, my child will come home from a weekend at dads and after being around his mother in laws cats, my child will be a mess for the next week. I'm sure some tightening starts in his chest in the first couple hours but this doesnt just go a way with a puff off the inhaler. It intensifies. By the time he is home, we have to go thru breathing treatments every 4 hours with his nebulizer and he is pretty much incapacitated.