Shambles I missed your post earlier and added an edit about it, I'm on a mobile phone and it takes me a while to write up these posts and I often miss posts while I'm writing it up.
Yeah man I totally feel you on the walking problems. I have a whole bunch of problems with my feet and legs to begin with and these guys make it worse. I have a badly fallen arch on my left foot and some arthritis in my big toe joint. I can manage it pretty well with orthotics and good conscious thought of my gait but mdpv and apvp practically have me limping by the end of it. It makes my muscles so tight that I can't really compensate for the problems I have and it's just a runaway effect - next thing I know the pain is migrating all the way up my back and everything just gets tighter and tighter. I'm sure the constant lack of food and water doesn't help my cause a damn bit.
The vapor from these guys does strange things to the mouth. It's taken a while for the damage to become evident to my lungs but I'm starting to cough a whole shitload now. It seems that during a binge the constant barrage of vapor to the lungs dries them up something fierce and it takes a while for them to respond. They are definitely responding now though, I'm bringing up lots of mucous and shit.