IJRAP International Journal of Research in Ayurveda and Pharmacy 2277-4343 Moksha Publishing House 10.7897/2277-4343.173118 A REVIEW ON NIDRA AS A METABOLIC REGULATOR: INTEGRATING CONCEPTS IN AYURVEDA WITH CIRCADIAN BIOLOGY Bithika Dolai * Shalini Prakash Kajal 11 -0001 167 172 The sleep-wake cycle is a homeostatic process regulated by circadian rhythm. In Ayurveda, Nidra (sleep) is considered one of the components of Trayopastambha (the three pillars of life). Proper sleep is essential for maintaining nourishment, strength, cognitive clarity, and physical and mental well-being. Modern lifestyle instigates a dual crisis of sleep disorders and acquired metabolic diseases like type 2 diabetes mellitus (T2DM), obesity, dyslipidaemia, etc. This review aims to integrate the Ayurvedic perspective on Nidra (sleep) and its role as a metabolic regulator. Also understand the concept of Kale Nidra (timely sleep) with evidence from modern circadian biology. According to Ayurveda, timely sleep is associated with Agnidipan (optimal metabolic activity), Pusti (proper nutritional status), and Dhatusamya (homeostasis). A conceptual parallel is found in circadian biology; synchronization of the ‘master clock’, the Suprachiasmatic Nucleus (SCN), to the peripheral oscillators in different organs is essential for normal metabolism. Disruption of this rhythm leads to impaired Agni and the formation of Ama, which results in diseases. Current research reflects this, linking sleep deprivation to insulin resistance, dysregulated hunger hormones, and elevated cortisol levels. The role of Clock genes in tissue-level metabolism provides an analogy to the concept of Dhatwagni. Metabolic health is inseparably linked to the circadian integrity of Nidra (sleep). Synchronizing sleep patterns with circadian rhythm helps to restore synergy between Agni and metabolic health. Timely sleep, being a modifiable factor of the pathophysiological loop, can be administered as a potent non-pharmacological tool for the global surge in metabolic disorders. Nidra Sleep disturbance Circadian rhythm Metabolic disorders