The habit of sleeping while listening to music, or watch TV to fall asleep, or to let the light in the room is brightly lit, it's hard to break, and by
some such conditions makes them fall asleep faster. But in reality after waking them feel more tension (stress). Some even felt like a sleepless night.
By the time we actually sleeping brain never sleeps. The brain is always running activities, although not as busy as in when you wake up, the body's metabolic system running. At night, with decreasing activity of the body, brain wave rhythms also declined. But if we sleep while listening to music, television, alive or room lights were burning brightly, the sound or light waves emitted by such equipment be accepted by our senses of sight and hearing.
Sound waves received by the hearing aid in the ear and keep the light waves can penetrate the eyelids and received by the retina and the lens of the eye. These waves will be transmitted to the brain. Rest of the brain should be stimulated to get back to work and process incoming information.
If this goes on all night, meaning we only sleep by outside bodies, but not by the brain. The brain will continue to work to process the incoming information. So do not let your brain is tired of having to keep working at night, while during the day the brain will also be squeezed by our routine.