Bala (Trividha Bala, Ojas and Vyādhikṣamatva)

Bala is the Āyurvedic concept of strength, vitality, functional reserve, endurance, and the capacity to sustain physical and mental activity. Its classical threefold classification comprises Sahaja Bala, present from birth; Kālaja Bala, varying with age and season; and Yuktikṛta Bala, developed through suitable diet, activity, conduct, medicines, Rasāyana, and other rational measures. Ojas is described as the supreme essence of the Dhātus and as the vital basis whose functional expression is closely related to Bala. Vyādhikṣamatva denotes the capacity to oppose disease strength and to prevent disease occurrence or recurrence. This chapter consolidates the classical definitions, determinants, seasonal variation, assessment, and enhancement of Bala; the origin, seat, qualities, forms, functions, depletion, disorders, and management of Ojas; and the relationship of Bala and Ojas with Prakṛta Kapha, Agni, Dhātu excellence, Sātmya, Sattva, and clinical treatment tolerance. It also examines Vikāravighātabhāva and Vikāravighātābhāva as determinants of disease manifestation. Modern comparisons with immunity, physiological reserve, resilience, nutrition, and host defence are used only as limited functional parallels and not as direct equivalences.