Re: Interval zapping no longer recommended by Dr. Clark!?

Can someone please tell me where she says this? The original interval times are given in her book with a good explanation and works great for me. The one time I fell asleep with my zapper on, I woke up 2 hours later with a painful hole burned into my skin. "Turn it on and leave it on" for how long and why? This claim should have the source cited but does not.