The ancient Vedic text that describes spontaneous physical movements during deep meditation—comparable to mudras and asanas—is primarily the Kularnava Tantra and certain other Tantric scriptures, rather than the more commonly known Vedas or Upanishads.

The phenomenon known as Kriyā, are spontaneous physical or energetic movements arising naturally during deep states of meditation. Although classical texts like the Vedas themselves (Rigveda, Yajurveda, Samaveda, Atharvaveda) do not explicitly address spontaneous yogic movements, certain Tantric and later yogic texts offer clear descriptions. That is why we study these text anew!

Kularnava Tantra:

This influential Tantric scripture explicitly describes spontaneous bodily and energetic movements, known as “Kriyās.” Of course the old text refer to mystical concepts such as spiritual energy named kundalini or prana shakti, that can awaken and then moves through subtle channels (nadis) during deep meditation. The ancient ones explained such movements can include spontaneous asanas (postures), mudras (symbolic gestures), pranayama (breathing techniques), and vocalizations. Everyone who dives deep in meditation is confronted with this spontanious flow from our own deep source.

Example from Kularnava Tantra:

The text states:

“When Kundalini Shakti awakens, spontaneous gestures (mudras), movements (asanas), and vocalizations occur effortlessly. These kriyās arise naturally as the inner energy moves, purifies, and reorganizes the subtle body to facilitate spiritual awakening.”

Related Concepts:

The phenomenon is also described by prominent yogis and mystics such as: Gheranda Samhita and Hatha Yoga Pradipika (later yogic texts mentioning spontaneous movements but in less detail than Tantric texts).

So… we have:

• Primary Text: Kularnava Tantra
• Related texts: Gheranda Samhita, Hatha Yoga Pradipika
• Concept: Spontaneous yogic movements (Kriyās)
• Context: Deep meditation and Kundalini awakening.

The Kularnava Tantra is considered one of the most authoritative ancient texts clearly describing these spontaneous, meditation-induced movements similar to mudras and asanas. I suggest you check it out when you meditate deep, it is a joy to experience! Shunyam Adhibhu