What are signs of overwhelm or over-training?

Signs of acute over-training/overwhelm:

All of these symptoms are merely signs that the nervous system has reached its peak capacity to adapt to the stimulus. They represent only temporary discomfort meant to act as a cue to decrease the stimulation intensity, and do not present any kind of long-term dangers. (PMP 3.0 is very safe.) By ceasing use of the Primary Meditation Tracks at this stage and instead using the Releasing Tracks on a daily basis, you will still experience profound states of meditation, but without the heavy carrier frequency stimulation offered by the Primary Meditation Tracks.

The Releasing Tracks contain biofield frequencies and evoke brainwave patterns especially suited for deep recovery and release.