Diuresis

Overview
Diuresis is the increased production of urine by the kidney.

Types and causes
The kidney normally produces up to 250 L of "pro-urine" (glomerular filtrate) per day, but reabsorbs most of this before it reaches the bladder.

Polyuria is increased diuresis. This may be due to large fluid intake, various illnesses (diabetes insipidus, osmotic diuresis due to diabetes mellitus or hypercalcemia) or various chemical substances (diuretics, caffeine, alcohol). It may also occur after supraventricular tachycardias, during an onset of atrial fibrillation, childbirth, and the removal of an obstruction within the urinary tract. Diuresis is restrained by antidiuretics such as ADH, angiotensin II and aldosterone.

Cold diuresis is the occurrence of increased urine production on exposure to cold.

Substances that increase diuresis are called diuretics. Coffee is an example of a proposed diuretic.

Substances that decrease diuresis allow more vasopressin or antidiuretic hormone (ADH) to be present in the kidney.

High-altitude diuresis occurs at altitudes above 10,000 ft and is a desirable indicator of adaptation to high altitudes. Mountaineers who are adapting well to high altitudes experience this type of diuresis. Urine output is thus an important indicator of adaptation to altitude (or lack thereof). Persons who produce less urine even in the presence of adequate fluid intake probably are not adapting well to altitude (Hackett 1980; pp. 54, 62).