Some physical and psychic signs can be seen as the Kundalini energy rises and moves through the chakras. Yogis have talked about how the body shakes before the Kundalini wakes up and the explosion of heat that moves like a current through the Sushumna. When the Kundalini starts to rise, people may hear sounds inside their heads like a waterfall, bees buzzing, a bell or flute, ornaments jingling, or other similar sounds. Even though the yogi’s head might start to feel dizzy and his mouth might start to drool, he keeps practicing until he can hear the sound that is the deepest, most subtle, and least affected by anything (Anahata nad). When the yogi closes his eyes, he sees many different things, like dots of light, flames, and geometric shapes. When a yogi reaches the highest level of illumination, these forms fade away and are replaced by an inner brightness of very bright, pure light.
Dhyanyogi Madhusudandas, a modern guru who practices Kundalini Yoga according to its traditional methods, lists the many signs and symptoms that an aspirant may experience, such as creeping sensations in the spinal cord, tingling sensations all over the body, heaviness in the head or sometimes giddiness, automatic and uncontrollable laughing or crying, hearing strange noises, seeing visions of deities or other spiritual beings, and so on.