The origin of Raga-the nucleus of Indian classical music (ICM)-dates back to the Vedic era with its identifiable roots in the Sama Veda [1,2]. The prototype monotonic Rig Veda recitation was originally developed to include only three notes i.e. a principal note, a higher note (Udatta), and a lower note (Anudatta) which was modified in the Yajur Veda to include a tetra chord with two principal notes and two accents. This tetra chord was further refined in the Sama Veda with the addition of three more notes, making the first scale of seven notes used to recite the Vedic hymns [3,4]. This scale of seven notes (Saptak) formulated to chant the Sama Veda, became the first Raga, closely resembling to Raga Kharaharapriya or Kafi of ICM [3,4].

As defined by the World Music Maestro-Pt. Ravi Shankar, “The Raga is a scientific, precise, subtle, and aesthetic melodic structure with its own peculiar creation, consisting either of a full seven note octave, or a series of six or five note octave(s), or a combination of any of these, composed in an ascending (Aroha) and descending (Avaroha) order, along with a subtle difference in the expression/omission/emphasis of particular note(s), or the use of microtones, that makes the Raga” [5]. Thus, Raga is a defined melodic structure that constitutes the “nucleus” of ICM system-regardless of its bifurcation as North Indian Hindustani Music or South Indian Carnatic Classical Music [1,2].

While todays Indian Classical Music is very commonly heard as Ragas, its existence and evolution is rooted in the ancient Yogic system known as “Nada Yoga” [6-8]. Yoga in general is defined as the body-mind-spirit regulatory system that integrates gross body or “Soma” (Sthula Sharira) with subtle body or “Psyche” (Sukshma Sharira), via functional energy center(s) (Chakras) that are postulated to govern the gross body [9-11]. Nada Yoga is the Yogic practice of body-mind-spirit integration through internal/Anahata (e.g. mediation) or external/Ahata (e.g. mantras/chanting/music) sound(s), that resonate in the body through defined sound frequencies, vibrating specific energy centers (Chakras) [6-8]. Humans have mechanoreceptors (Pacinian Corpuscles) located all over the body including skin, tendons, bones, most abdominal and sexual organs, which are sensitive to vibrations and therefore are able to resonate with sounds, making it plausible to believe that their stimulation by musical sounds will produce an effect [12]. Integrative therapeutic use of Raga (Raga Chikitsa/Therapy) is a part of Nada Yoga, in which defined melodic structure of a given Raga is aimed at synchronizing, vibrating and activating designated Chakra(s) [6,8,13-16].

Chakras are the vital energy hubs of the subtle body system [9-11]. This subtle body or “Psyche” model (Sukshma Sharira) shows close correlation with the nerve-plexuses formed by the autonomic nervous system (ANS) of the gross body or “Soma” (Sthula Sharira), with its sympathetic and parasympathetic control of lateral/peripheral dominance, relaying back to the central nervous system (CNS) (Figure 1) [9,10,17]. The scientific observations show near-perfect alignment of major ANS-nerve plexuses with each of the Chakras, as confirmed by cadaveric [18] electro-photonic [8] and contemplative cross-referencing (Figure 2) [9,10].

The Chakra subtle body system consists of seven prime Chakras i.e. Mooladhar (Root), Swadhishthan (Sacral), Manipura (Solar), Anahata (Cardiac/Heart), Vishuddhi (Throat/Pharyngeal), Ajnya (Carotid), Sahasrara (Carotid) Chakras, interconnected with the energy channels called “Reeds” or “Meridians” known in Vedas as “Nadis” [10,14] (Figure 2). There are three principal Meridians including right “Masculine” Nadi (Pingala) (Figure 2, Red), left “Feminine” Nadi (Ida) (Figure 2, Blue), and central “Neutral” Nadi (Sushumna) (Figure 2, Yellow Dotted Lines). The Masculine and Feminine Meridians intersect and pass through successive “Chakra”-points, finally converging into right and left nostrils respectively, after passing through the Vishuddhi Chakra (Pharyngeal Plexus) [8,10] (Figure 2). Congregation of all Chakras (Mooladhar, Swadhishthan, Manipura, Anahata, Vishuddhi, Ajnya, Sahasrara), through peripheral and central Meridians (Figure 2, Red-Pingala-Masculine, Blue-Ida-Feminine, Yellow Dotted-Central Sushumna), is aimed at attaining total mind-body integration and tranquility [10,13,15,16].

Every Chakra is correlated with specific physiological, psychological, and spiritual characteristics [8]. Each Chakra governs specified physiological function(s) including respiration, excretion, reproduction, metabolism, circulation, sensation, motor, and proprioception [8,10]. Mooladhara Chakra is responsible for security, stability, survival, and regulates excretion and reproduction; Swadhishthana Chakra is responsible for creativity, emotions, and governs reproduction, regeneration; Manipura Chakra is responsible for power, vigor, ego, and governs digestion, assimilation, metabolism; Anahata Chakra is responsible for love, passion, affection, and governs respiration and circulation; Vishuddhi Chakra is responsible for purity, discriminative thinking, and regulates effective speech and communication; Ajnya Chakra is known as the “Sixth Sense” that is responsible for analytical reasoning, intelligence, and governs rational thinking, intellectual ability; lastly, Sahasrara Chakra governs knowledge, wisdom, spiritual enlightenment, and makes one aware of self-consciousness, oneness with the Supreme [8-10] (Table 1). Furthermore, it is considered that each Chakra is also associated with bodily endocrine glands i.e. Mooladhara with adrenals, Swadhishthana with gonads, Manipura with pancreas, Anahata with thymus, Vishuddhi with thyroid, Ajnya and Sahasrara with Cerebrum, pineal, Hypothalamo-Pituitary-Adrenal (HPA) axis [8-10].

Ragas are postulated to activate Chakras via two principal mechanisms: Association of Swaras with Chakras, and Association of Ragas with Chakras.

Association of Swaras with Chakras

The seven basic notes of Raga (Swaras) are associated with each of the seven prime Chakras and their corresponding Plexuses (Figure 1). i.e. Mooladhar (Coccygeal) (Sa), Swadhishthan (Sacral) (Re), Manipura (Solar) (Ga), Anahata (Cardiac) (Ma), Vishuddhi (Pharyngeal) (Pa), Ajnya or Agnya (Carotid) (Dha), Sahasrara (Carotid) (Ni) [5,6,13]. Each Raga contains a predominant Swara called the “Vadi” Swara which is frequently used in the rendition [3-5]. The Raga with a specific Vadi Swara will activate a Vadi-Swara-specific Chakra [2,5]. For example, Raga Jog with “Ma” Vadi Swara is capable of vibrating Anahata Chakra (Table 1). In addition, each Raga is composed of Shuddha (Major) or Komal (Minor/Flat) or Tivra (Sharp) Swaras. The Raga that contains all Shuddha (Major) seven Swaras is called the “Sampurna” Raga, and by virtue of containing all seven Shuddha (Major) Swaras in its composition, a “Sampurna” Raga can activate all Chakras [2-5]. For example, Raga Mand Mishra is a “Sampurna” Raga which can activate all seven Chakras. On the other hand, Raga Mohanam/Bhupali, containing all Shuddha (Major) Swaras except Ma and Ni, can activate all Chakras except Anahata and Sahasrara Chakras [13].

Association of Ragas with Chakras

Besides Swara-specificities, defined designation of Ragas with specific Chakras also can activate specific Chakras [5,6,13] (Table 1). Each Chakra can be activated with a particular Raga designated to be associated with that particular Chakra [19] (Table 1). As detailed in Table 1, Raga Shyam Kalyan can activate the Mooladhara Chakra, Raga Yaman helps activate the Swadhishthana Chakra. Raga Abhogi can activate the Manipura Chakra while Ragas Bhairav and Raga Durga can activate Anahata Chakra. Raga Jayawanti is able to activate the Vishuddhi Chakra, and Raga Bhup can activate Ajnya Chakra, allowing the Kundalini pass through the Ajnya Chakra entering the Sahasrara Chakra, causing a person to reach a state of selfless awareness and tranquility [16]. Chakras are known to be activated by Swaras, Chakra-associated Ragas, and also by chanting of Chakra-specific “Beej Mantras” (Vedic Seed Mantra with defined Hz that activates specific Chakra) [8,13,16]. Ragas can activate specific Chakras maintaining optimum spin, which allows the Kundalini energy to rise, energize and nourish the Chakra(s). Ragas influence Chakras to maintain their optimum spin, ensuring a physiological balance [16].

Empirical evidence linking sound/music vibrations to Chakra activation

Chakra activation/balancing and music therapy are part of the traditional Indian healing system, however, very little is known about the effect of music on Chakra activation [9,10,13]. Some of those few empirical evidences linking music vibrations to Chakra activation include an exploratory study that evaluated effects on individual Chakra activation through a maneuver of six cycles of ascending/descending Swaras – each cycle included singing of ascending notes “S”, “R”, “G”, “M”, “P”, “D”, “N”, “S” (higher) followed by descending notes “N”, “D”, “P”, “M”, “G”, “R”, “S”, followed by 3 cycles of chanting “Om”, with the whole intervention lasting for 12 min, conducted in the controlled environmental conditions. Increase in the body temperature was considered as one of the physiological changes as a result of Chakra activation [20]. This study with a single 12 min session of singing ascending and descending notes followed by “Om” chanting, elevated whole body temperatures from feat to head in all subjects, confirming the activation of all Chakras [20]. Another randomized crossover pilot study investigated immediate effects of Nada Yoga meditation using Chakra-specific “Beej Mantra” on the energy levels and activation of aligned Chakras in healthy volunteers, assessed by electro-photonic imaging measurements of Chakra-specific Hz energy [8]. The results showed enhanced activation of Mooladhar, Manipura, Anahata, and Vishuddhi Chakras, and moderate activation of Swadhishthana, Ajnya and Sahasrara Chakras [8]. Unfortunately, there is insufficient documentation regarding individual variability of Chakra-activation experiences.

Therapeutic directives and clinical applications of Ragas

The documentation of curing Mussolini’s insomnia by Pt. Omkarnath Thakur’s Raga Puriya rendition is the oldest evidence presenting clinical application of Raga [21]. Regarding current clinical Raga applications, the “ClinicalTrial.gov” search rendered only five studies that used Indian Raga intervention(s) either in vocal or instrumental form for treating different health disparities (Table 2). A randomized controlled trial (NCT03790462) evaluated the effects of Raga Puriya, Hindol, and Todi on psychological and social stress, as assessed by salivary stress biomarkers (Cortisol, Amylase), electroencephalogram (EEG), heart rate variability (HRV), blood pressure (BP) and anxiety assessed by State Trait Anxiety Inventory (STAI) scores. Other randomized controlled trials tested the effects of Ragas Ahir Bhairav, Kausi Kanada, Bhimpalas (NCT02691585), and Raga Bhimpalas only (NCT02147366) on hypertension, EEG and HRV. Another randomized study (NCT04351217) evaluated the effects of Raga Ahir Bhairav and Bhairavi on craving reduction in alcohol dependency/syndrome. A randomized study on the effects of Indian classical music-Melodic Intonation Therapy (MIT, Raga not specified) was compared with standard speech rehabilitation therapy in post-stroke and non-fluent aphasia (NCT06323330). None of these clinical trials have posted the results yet.

Multidisciplinary integrative approach in healing

Multidisciplinary integrative medicine approaches including music therapy have gained credence in recent years due to limited efficacy of pharmaco-mono therapies [22,23]. The exploration of non-pharmacological alternative and complementary medicine has set the stage for the evolution of integrative approach in health and healing which supports the mind-body connection [24,25]. The rationale behind integrative health hails from ancient healing practices such as Yoga [26]. Nada Yoga constitutes a type of Yoga that deals with body-mind-spirit integration through internal/Anahata (such as mediation) or external/Ahata (such as mantras/chanting/music) sound(s) that vibrate specific energy centers (Chakras), resonating in the body-organs with specific sound frequencies [6,8]. Integrative therapeutic use of Raga (Raga Chikitsa/Therapy) is a part of Nada Yoga, in which defined melodic structure of a given Raga synchronizes, vibrates and activates associated Chakras [6,8,13]. In summary, Raga offers an integrative healing practice that links physiological, emotional, sociological, psychological, and spiritual dimensions of the human body, thus connecting “Psyche” (Sukshma Sharira) with “Soma” (Sthula Sharira).