Circadian and Metabolic Timing in Electrolyte Regulation: A Coupled Clock Model Linking Metabolic Load, Chloride Terrain Signals, and Cardiovascular Stress, Lantern of Sulfur, Concept A, v12.1, March 2026

Electrolyte regulation is often treated as a static biochemical process, yet many of the systems governing electrolyte balance operate on circadian timing cycles. Hormonal signaling, renal ion transport, hepatic metabolism, hydration behavior, and autonomic regulation all exhibit strong daily rhythms coordinated by hypothalamic circadian control.This preprint proposes a coupled clock model of electrolyte regulation in which circadian rhythm and metabolic timing interact to maintain physiologic terrain stability. In this model, circadian timing systems coordinate regulatory signals that influence fluid balance, renal ion transport, and neurohormonal pathways including the renin–angiotensin–aldosterone system (RAAS).Metabolic rhythms—such as meal timing, fasting intervals, and fuel switching between glucose and ketone metabolism—may impose physiologic load on these regulatory systems. When circadian timing and metabolic rhythm become misaligned, regulatory interpretation of hydration and electrolyte signals may shift, potentially altering renal chloride–bicarbonate handling and generating recognizable electrolyte terrain patterns. The paper introduces a conceptual framework linking: • circadian regulatory timing• metabolic rhythm and fuel switching• hydration signaling and bile–metabolic coupling• renal ion transport execution• downstream electrolyte terrain signals Within this framework, persistent chloride–bicarbonate drift detectable on routine chemistry panels may represent an early marker of regulatory stress rather than a late marker of established disease.This paper represents the regulatory timing layer of the Lantern of Sulfur Concept A series. Companion papers describe the other two layers of the system:• Metabolic execution layer — Chloride–Bicarbonate Terrain Shifts in Electrolyte Regulation, Lantern of Sulfur, Concept A, v12.1, March 2026• Clinical cardiovascular expression layer — Reversible HFrEF-The Pattern Five Specialties Missed, Lantern of Sulfur, Concept A, v12.4, March 2026Together these papers describe a vertical regulatory sequence linking physiologic timing architecture, metabolic load patterns, electrolyte terrain signals, and cardiovascular expression. The framework is hypothesis-generating and intended to support further investigation into the interaction between circadian physiology, metabolic rhythm, and electrolyte regulation.