Hibeta (20-35 Hz) - This brain wave is responsible for our fight/flight response. While this brain wave does keep you safe and alert from a bear attack or a car crash, it is not essential for sitting in a chair while watching television. Too much Hibeta activity can indicate overarousal, such as anxiety, hyperactivity, obsessiveness, or sleep difficulties. Too little Hibeta activity can indicate under-arousal, such as delayed reaction time and trouble solving complex problems.