Physical level – Helps in harnessing the “Right Brain” which is the seat of emotions, creativity etc. While modern science focuses on developing the left brain; the Right brain is developed through Chanting Shlokas, Devoted singing of Bhajans, etc. There is a flow of positive energy in our body. Research shows that positive hormones like Serotonin, Dopamine, GABA, etc. are released during chanting of bhajans and shlokas.
Vital Energy Level – The breath-force also called as vital energy or ‘Prana’ is regulated and harmonized by chanting of bhajans. A natural pranayama effect is caused by Namasankeerthanam.
Mental/ Emotional Level – There is reduction in stress, anxiety, depression leading to prevention and cure of diseases (originating from the Manas level called as ‘aadhi’). The emotions are purified by chanting bhajans and they unblock any stress related blocks in varied layers of the body.
Intellectual Level – The logical faculties of the brain are activated and the knowledge into meta-physical aspects are gained by the Bhakthi Yoga maarga.
Spiritual level – Overall there is happiness that is eternal and which is anchored to someone eternal.
ध्यायन् कृते, यजन् यज्ञैः त्रेतायां, द्वापरे अर्चयन् |
यदाप्नोति तदाप्नोति कलौ सङ्कीर्त्य केशवम् ||
dhyāyan kṛte, yajan yajñaiḥ tretāyāṃ, dvāpare arcayan |
yadāpnoti tadāpnoti kalau saṅkīrtya keśavam ||
-- (Bhagavannamakaumudi by Lakshmidhara)
What we get by doing Dhyanam in Kritayuga, Shrouta-Yagnyas in Tretayuga and by pooja/ devatha archana in Dvaapara yuga ; that we can get in Kaliyuga by chanting the name of Bhagavaan.