This is the classic flow state while you are awake but still relaxed and not actively overthinking. This state is the connection between the conscious and the subconscious mind. Experienced meditators have increased Alpha activity shown in studies monitoring the EEG activity. It increases the ability to recall memories, lessens discomfort and pain and reduces stress and anxiety. This state is used in hypnosis as well. Alpha Brainwaves are making your learning and studying more effective.
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