Sandhyavandana (Sanskrit: संध्यावन्दन sandhyāvandana) is a mandatory[according to whom?] religious ritual that needs to be performed by all twice-born people of Hinduism. Especially brahmins who are initiated into the sacred thread ceremony called as Upanayanam, and instructed in its execution by a Guru (a qualified spiritual teacher). Sandhyavandanam consists of excerpts from the Vedas that are to be performed thrice daily at morning (prātaḥsaṃdhyā), at noon (mādhyānika), and in the evening (sāyaṃsaṃdhyā).
Sandhyavandanam literally means salutation to Sandhya. Sandhya literally means transition moments of the day namely the two twilights : dawn and dusk and the solar noon. Thus Sandhyavandanam means salutation to twilight or solar noon
The term saṃdhyā is also used by itself in the sense of "daily practice" to refer to the performance of these devotions at the opening and closing of the day.
Sandhya Vandhana is the essence of Yoga & Meditation
1.Achamana consists of Nama Sankirthana
2.Pranayama is the Breathing exercise
3.Gayathri japa is meditation
4.Navagraha tarpana is to please nine planets daily
5.Upasthanam is prayer to Sun god & Lord Varuna
Main components of Sandhyavandanam
Aachamana + Angavandanam - Sipping water three times + purifying parts of the body
Ganapathi Dhyanam - Requesting Lord Ganeshaa for cessation of obstacles
Pranayama - (Prana) Breathing (aayamaha) regulation exercise controls Pranamayakosha (Physiological aspect). Pranamaya kosha include these 5 systems - Prana (respiratory system), apana (excretory system), vyana (circulatory system), samana (digestive) and udana (reversing system). Influences Anamayakosha (Anatomical aspect) and Manomayakosha (Emotional aspect). There are 2 types: Kevala pranayama (Done silently - focus is on body) and Sagarbha pranayama (recommended) (With mantra - health improves but we remain detached from body). Done 3 times to 10 times.
Meaning of Mantra - Pranava - Om means eeswarah (implying that God is everything). Vyahrithihi) - Bhu, bhuvaha etc. refer to 7 upper lokas (other 7 lower lokas are implied) are all God. Gayatri - Simple meaning - I meditate upon the light of the sun which activates our intellient) Gayatri shiras (again says that God is everything - All waters (aapo), lights (jyothi), essences/nourishment(raso), God's nourishment (amrutham) is God).
Sankalpam - Taking the resolve - has benefit of auto-suggestion (telling yourself that this is your focus for next 15 odd minutes).
Jalaprashanam or Marjanam
Navagraha Kesavathi Tarpana
Chanting of the Gayatri mantra, traditionally, is done 32, 64 or 108 times (it depends on the person doing sandhyavandana; he can chant any number of times. "YathaSakti Gayatri mantra japam karishye" was the sankalpam in Sandhya vandana), depending upon the prescriptions of the practitioner's Veda and Sutra, an integral part of Sandhyavandanam. In addition to the mantra, the ritual of saṃdhyā includes other rites that are purifying and preparatory (Sanskrit: śuddhi mantras), serving to prevent distracting thoughts and bring focus to the mind. Some of these are propitiatory libations of water to the Gods of the planets and of the months of the Hindu calendar, atoning for Sandhyavandanams not performed and atoning for sins committed since the last hour of Sandhya. In addition, one of the most important rituals of Sandhyavandanam involves worshiping the Sun as Mitra in the morning and worshiping Varuna, in the evening.
Each Shakha of the holy Veda has its own unique way of sandhyavandanam. Shatatapa Smriti says a Dwija who doesn't do sandhyavandanam at least once will be a dog in the next birth. During Ashoucham (during death of any relative or birth of a child) sandhyavandanam is done without water and Darbham (Kusha grass). On Trayodashi, during sayam sandhya minimum gayatri japam and silence is prescribed by some vedik scholars. There are few additional mantras in Navagraha Kesavathi Tarpana for Bodhayana Sutra. They include Yama mantras, in addition to Navagraha Kesavathi mantras.
Daily duties of Brahmins
Doing Sandhya vandhana first creates the eligibility for a brahmin to do all rituals following it.Rituals done without doing sandhyavandhanam is regarded as fruitless by Dharmaśāstra. Thus, sandhyavandhana forms the basis or regarded as the foundation for all other vedic rituals. After doing Sandhyavandhana dhyannika Sandhya to get rid off sins occurred due preparation of lunch like boiling rice,cutting vegetables, burning firewood etc. In Vaishvadeva homa rice cakes are offered to vishvadevas (all devatas).
Science behind the practice
Regular recitation of Sandhyavandanam, helps regulating the blood pressure and the postures in which these the entire practice is performed helps in overall muscle rejuvenation.