Calculated serum osmolality (Dorwart-Chalmers) reflects total plasma solute concentration and drives ADH release and thirst.
Calculated serum osmolality (Dorwart-Chalmers) reflects total plasma solute concentration and drives ADH release and thirst. Chronic mild hyperosmolality from habitual under-hydration is linked to metabolic syndrome, kidney disease progression, and cognitive decline.
High: dehydration, hyperglycaemia, hypernatraemia, azotaemia. Severe hyperglycaemia (HHS) is a medical emergency. Low: overhydration, SIADH, adrenal insufficiency, hypothyroidism.
High: thirst, dry mouth, reduced urine output, confusion, lethargy. Severe: seizures, coma. Chronic mild elevation: brain fog, fatigue, poor concentration.
Adequate fluid intake (~30–35 mL/kg/day). Electrolyte-balanced hydration from vegetables, fruits, soups, and mineral water.
High-sodium, high-sugar, high-protein diets. Alcohol causes transient osmolality rise followed by diuresis-driven dehydration.
Educational information only — not a diagnosis. Every Pheno result is interpreted in context and reviewed by a physician.
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