Reading can be a wonderful (and healthy) escape from the stress of everyday life. Simply by opening a book, you allow yourself to be invited into a literary world that distracts you from your daily stressors. Reading can even relax your body by lowering your heart rate and easing the tension in your muscles. A 2009 study at the University of Sussex found that reading can reduce stress by up to 68%. It works better and faster than other relaxation methods, such as listening to music or drinking a hot cup of tea. This is because your mind is invited into a literary world that is free from the stressors that plague your daily life.
I wouldn’t personally recommend listening to delta wave frequencies for depression, so I’m not sure who advised you to do that? People with depression usually have a higher ratio of theta and delta wave activity, so I would normally recommend listening to high alpha wave and low beta wave frequencies, to help balance things. I have some 10Hz alpha tracks for serotonin release, which you can try for free on my YouTube channel here: https://www.youtube.com/watch?v=3NSUcuzpRcY&list=PLveg0IEcZWN6T86nhmSrdwG2kMQtcLRou. I also recommend you give these SMR (low beta wave) tracks a try: https://www.youtube.com/watch?v=HGTvBbrEwZQ&list=PLveg0IEcZWN7yaMaKr8F-eWHALk2_zGqY. I hope that helps.
The activity of neurons generate electric currents; and the synchronous action of neural ensembles in the cerebral cortex, comprising large numbers of neurons, produce macroscopic oscillations. These phenomena can be monitored and graphically documented by an electroencephalogram (EEG). The electroencephalographic representations of those oscillations are typically denoted by the term 'brainwaves' in common parlance.