I can't say anything about training it, but beside the usual sleepiness, at >1000 ppm I get a feeling of swelling eyeballs and tingling teeth/dentures. I've bee

I can't say anything about training it, but beside the usual sleepiness, at >1000 ppm I get a feeling of swelling eyeballs and tingling teeth/dentures. I've been this way as long as I remember.