1. Introduction Every day for all living beings begins with the sunrise for there is no life on earth without the sun. The Sun is indeed worshipped as a god in various cultures by the name of Mithras in Persians, Apollo in Greeks, Osiris in Egyptians, and Surya in the vedic period of India and so on [1]. In Ramayana, Sage Agasthya advised Lord Sri Rama to worship the sun god by chanting Aditya Hridayam to achieve victory in his encounter with the demon king Ravana. These verses depict the various forms and names of the sun god, praising his glory and his 12 forms (signifying the shape of 12 months of a year) in the Yuddha Kanda of Ramayana [2]. The sun is considered as the Pratyaksha swarupa (the ultimate power visible to the eye), which represents truth, a manifestation of knowledge, and the giver of intellect & prosperity. The sanctity of the sun god is explained in a chapter containing 132 verses named ‘Surya namaskar’ in Taittriya Aranyaka under Krishna Yajur Veda. This is being chanted as a ritual practice among South Indians along with the performance of namaskara (salutation) at the end of each verse [3]. In present times Suryanamaskar is both a physical as well as a spiritual practice. It was inserted into yogic practices owing to its immense potential in maintaining the practitioner's physical and mental health which is the basic requirement for higher yogic practices. We reviewed this spectacular practice of various schools through standard textbooks published by the respective schools and highlight its importance in disease management through research articles indexed in PubMed/ Scopus/web of science.

2. Origin of Suryanamaskar

‘Suryanamaskar’ or the ‘sun salutation’ a set of dynamic postures, is considered neither an Asana nor a part of traditional Yoga. Suryanamaskar is a complete physical exercise that is believed to be conceived and propagated by the King of Aundh, Late Shrimant Balasaheb Pant Pratinidhi in the 1920s [4] and later by Sri K V Iyer, and Sri Krishnamacharya. The Danda exercises explained in Vyayama Dipika were found to be the basis for Suryanamaskar models presented by Sri Krishnamacharya [5]. Dandaal is an ancient common and important physical training practiced in India by wrestlers, and

Beeja mantras are generally used during fast Suryanamaskar where chanting of twelve names is difficult. These are chanted four times repeatedly during the performance of one complete round of Suryanamaskar. The twelve steps involved in this group of Asanas as per Bihar School of Yoga tradition, the mantras and Beeja mantras along with the associated Chakra for each posture have been tabulated in Table 1

3. Suryanamaskar from other schools of Yoga

• Krishnamacharya Vinyasa Yoga tradition

This comprises thirteen Vinyasas (postures). The first Vinyasa is Samasthiti/pranamasana and then Tadasana/Hasta uthanasana. This is followed by Uttanasana/Pada hasthasana, and Utkatasana (hip stretch pose). Then the practitioner lifts the heels and jumps landing on big toes to Chaturanga dandasana. Then comes the Danda samarpana (complete surrender; similar to Ashtanga namaskar). Coming back from this posture to again Chaturanga dandasana, the practitioner performs Urdhwa mukha swanasana (similar to Bhujangasana), and then Adhomukha swanasana (Parvatasana). Then this is followed by Utkatasana, Uttanasana (Pada hasthasana), Tadasana and Samasthiti (Fig. 3). The performance of correct breathing and chanting of mantras while achieving a posture is strictly emphasized in Krishnamacharya Yoga. The practitioner starts with inhalation and breath is held during Samasthiti and focus shifts on the first mantra, and then inhaling smoothly while raising the arms for Tadasana, and the breath is held while chanting the mantra. Then exhalation while achieving Padahasthasana, inhale and then exhale while bending the knees to reach Utkatasana. The breath is held as a general rule in every posture while mentally chanting the mantra. Then the yogis/yoginis inhale and hold their breath while lifting the heels till landing on Chaturanga dandasana. While on this posture the practitioner exhales and breath is held out and then slowly exhales while changing from the previous posture to Danda samarpana [8]. Though there are some more variations of Suryanamaskar in this tradition we have considered the most common and easier version to compare it with other traditions.

• Sivananda Yoga Vedanta Centre tradition

This series includes Phalakasana as step 5 instead of Parvatasana during which the breath is held, and step 8 is named Adhomukha svanasana

• Benefits of Suryanamaskar

• Physical and physiological benefits

The mightiness of the sun and its energy if extracted properly gives great benefits to humankind. The dynamic movements in each step of Suryanamaskar make the body contract and expand its muscles alternatively and tone up the joints. This makes the stagnant blood at the inactive muscles and joints to be redirected back to the kidneys and lungs for purification. Regular practice of Suryanamaskar ensures proper and efficient functioning of not only the muscles and joints of the body but also stimulates the internal organs. Especially the stomach and other abdominal organs as it involves alternative stretching and compression at the abdominal area. Suryanamaskar also improves peristalsis of the intestines, stimulates blood circulation throughout the body, massages, and tones up kidneys so that wastes are efficiently eliminated from the body at ease, and helps the body to eliminate toxins through increased perspiration. Toxin elimination is an important process to maintain healthy skin and thus helps prevent skin diseases. Suryanamaskar enhances the gaseous exchange at alveoli and thus improves the rate of respiration. The immune system protects the body against the disease-causing agents by the production of antibodies and other mechanisms. Suryanamaskar increases the efficiency of the immune system [1]. Suryanamaskar increases the mobility of almost all the joints of the body evident from kinematics studies using three-dimensional motion capture in ten healthy Yoga practitioners [11]. Different poses of Suryanamaskar are reported to produce specific muscle activation patterns depending on the practitioner's skill levels [12]. Improvement in physical fitness of school children with Suryanamaskar practice was evaluated using cardiovascular parameters and pulmonary function. Improvement in muscle strength, involvement of isometric contraction, and chest expansion during different postures of Suryanamaskar have been reported. The effects of Suryanamaskar performed at different speeds revealed that fast pace Suryanamaskar is more similar to aerobic exercise and owing to increased muscle endurance and power. Whereas effects of slow pace practice led to a decline in cardiovascular parameters to normal levels similar to Yoga training [13]. Body mass index (BMI) is an important index

practice in Yoga practitioners [18,19]. Coronary artery disease patients were evaluated for various parameters pre and post-Yoga practice with a set of asanas including Bhujangasana (step 7) and Hastha uthanasana (step 2). This study reported a significant decrease or alteration in various associated physiological parameters namely heart rate, body fat, cholesterol, triglycerides, and LDL levels emphasizing the importance of these Asanas in such patients [20]. Suryanamaskar is recommended as a practice to improve cardio-respiratory efficiency both for healthy individuals and cardiac patients [21]. The practice of a panel of 5 Asanas including Bhujangasana (step 7) showed no significant difference in the systolic time intervals measured in 5 healthy regular Yoga practitioners. This report emphasized that the changes produced in cardiac function during the practice are within the normal functional limit of the heart [22]. Further, Suryanamaskar is suggested as an activity of optimal stress on the cardiorespiratory system. Total energy consumption of 13.91 kcal with an average of 3.79 kcal/min for one complete round of Suryanamaskar was observed in male volunteers from the Indian Army. Oxygen consumption was reported to be the highest while in Bhujangasana [23]. Another study in a 60 kg individual reported the expenditure of 230 kcals of energy/30 min practice session with four rounds of Suryanamaskar [24]. It is inferred that Age, weight, pace, and deep breathing impacts the energy expenditure which tends to vary for each scenario.

• Effects on endocrine functions

Suryanamaskar is often considered as a bridge between Sukshma Vyayama (Loosening Exercises) and the practice of other advanced Asanas and Pranayamas. It helps to relieve any kind of mental disturbance. Imbalance in mental health is often associated with or leads to an imbalance in hormones and thus it manifests as a disease or syndrome e.g. Diabetes, Thyroid dysfunction, and so on. Endocrine glands are toned and massaged by regular practice of this excellent group of Asanas. Suryanamaskar stimulates the brain centers and the associated nerve fibers running throughout the body. It is emphasized that in addition to the benefits that these group of Asanas bestows to each physiological system in the body, it also provides a balance between the circulatory, respiratory and endocrine systems with one another and thus helps in the prevention of diseases and so on [1].

Suryanamaskar is reported to activate all glands in the body including pituitary and adrenal glands both of which are responsible for positive neuroendocrine feedback for proper maintenance of GH and DHEAS levels [26]. Moreover, the pituitary gland is said to be the master gland controlling the switching on/off of functioning of all other glands/ organs. Anterior pituitary hormones are tropic hormones that stimulate the secretion of hormones from concerned target organs/glands [14]. This fact could be a probable indirect explanation that the practice of Suryanamaskar modulates the functioning of endocrine glands and thus improves the energy metabolism and paves way for postponing the aging process. However further scientific research evidence is needed to establish the direct connection between the performance of each step of Surya namaskar and the glands concerned.

Fig. 5. Pictorial representation of Suryanamaskar (Swami Vivekananda Kendra tradition): Pictorial representation of the flow of postures of Suryanamaskar as per Swami Vivekananda Kendra tradition. 1. Hastha uthanasana; 2. Padahathasana; 3. Ashwasanchalanasana; 4. Phalakasana or Dandasana; 5. Shashankasana; 6. Shashtanga namaskara; 7. Bhujangasana; 8. Parvatasana; 9. Shashankasana; 10. Ashwasanchalanasana; 11. Padahathasana; 12. Pranamasana [10]

5. Proposed daily practice of Suryanamaskar

We propose the daily practice schedule for various age groups. Starting from children, who are generally active and limitless flexibility, could be involved in fast or slow pace Suryanamaskar depending on their energy levels, need, and body conditions. Teenagers who have active metabolic patterns and are healthy are recommended to perform 12 to 24 rounds of Suryanamaskar followed by Yoganidra (Complete Relaxation Practice) and Pranayama. Middle-aged people are often down with lifestyle disorders these days and they are recommended 6e12 rounds of Suryanamaskar followed by Yoganidra, Pranayama, and meditation. Old age people who are below 70 years can practice Surya namaskar according to their comfort level both with regards to the number of rounds and the postures. These are suggested daily practices for the different age groups of people;

effective way to manage weight and physical fitness and improving cardiorespiratory fitness [29]. Thus, from a therapeutic viewpoint, this practice has immense potential as a one-man army to manage diseases like obesity and so on. The summary of research on Suryanamaskar towards disease management and the corresponding outcome has been listed in Table 3.

7. Discussion

Health is defined as “a state of complete physical, mental, and social well-being and not merely the absence of disease or infirmity” according to the definition of WHO [30]. The main purpose of Yoga is to achieve and maintain this state of health as defined. In contrast to all other Asanas which work on a particular part of the body, Suryanamaskar is a complete Health capsule for the whole body. We observe from the above discussions that, Suryanamaskar helps in mobilizing the joints and in increasing one's physical stamina by enabling them to breathe to their fullest capacity. Most importantly, it helps them to preserve the health of the spine by allowing them to sustain comfortably in sitting postures for a longer time during the practice of pranayama and meditation. Suryanamaskar is generally practiced as a capsule with other yogic…………

helps in keeping the mental health and the equilibrium of the state of mind, as metabolism and glands directly affect the mind. This is further substantiated from a study in college students which shows that Suryanamaskar helps to attain a quiet mind measuring several parameters in relaxation and stress dispositions. Suryanamaskar practice is suggested as an effective relaxation strategy on highly stressed college students [32] and further Suryanamaskar could be effectively used to improve neuromuscular functions [33]. Meditation is largely known to be a static procedure where the body is passive and the mind is being trained to be still. But some martial art traditions have moving meditation where the mind can be made focused even while the body is in movement in a completely organized and coherent manner with the breath. Surya namaskar becomes a more powerful moving meditation tool considering the physical posture, breathing component, the concerned body part being stimulated, and the concentration on the chakra associated with each posture. This is substantiated by the fact that the slow pace practice of Suryanamaskar resulted in nearnormal levels of cardiovascular parameters compared to elevated levels during fast Suryanamaskar [13]. Further high-speed Suryanamaskar resulted in higher energy expenditure than standard speed Suryanamaskar with a significant difference in the volumes of oxygen consumed and carbon dioxide produced [34]. These points are further supported by the results obtained while performing 4 rounds in 30 min which led to the average oxygen consumption of 26 ml/kg/min during each round [24]. Thus, it is proposed that a single group of Asanas can be tailored to produce distinct benefits by changing just the speed of practice. This unique property can be conferred only to Suryanamaskar and neither to any other asana practice nor other types of aerobic and physical exercises. It is clear from the above discussions that Suryanamaskar plays an important role in balancing the functioning of endocrine glands. This property helps to regulate/delay the transition period between childhood and adolescence in growing children, especially in females. Puberty and followed by Menarche is an important process in every female's life that prepares their body for reproduction. Due to environmental factors and food habits, Puberty/Menarche is advanced to an early age, when the body is not well prepared to undergo

of mental health of the body, and proper functioning of endocrine glands were also discussed. Highlighting the yogic point of view of the benefits of Suryanamaskar practice, the positive effects of Suryanamaskar on puberty, menstrual cycle, and childbirth were also emphasized. We conclude from the above points that the practice of Suryanamaskar is necessary not just for those who are regular yogic practitioners or spiritual seekers but for a common man, to maintain the physical, physiological, and mental health by spending very little time of their choice. If this practice is initiated to children at the age of 7 or 8 it helps grow better not only physically but also with great mental health. We propose that Suryanamaskar practice could be a group activity of the family to ensure total family health. Suryanamaskar is a boon for those who want to involve in yogic practices but yet not dedicate even an hour every day.

References