4 hours sleep in 40 minutes is a long meditation theta (synchronizes brain hemispheres in the frequency of 5 Hz). Compensate the time sleep about four hours. The background of this recording is the sound of constant frequency, which helps eliminate sound coming from the outside.

You can listen to this meditation all over the place and time when the only help ensure a comfortable position and forty minutes of free time. Meditation regenerates your vital forces, improves mood and concentration.

Close your eyes, get headphones and let yourself off for forty minutes. After all, you will feel rested and after about four hours of sleep.

Note: Do not listen to the recordings in their activities that require you to concentrate (eg, driving).