Urine time volume (also urinary time volume) includes the amount of urine that is excreted in a specified period of time. In all cases, this time period is 24 hours. The measured volume of urine is used primarily to assess kidney disease. Normally, about 1.5 to two liters of urine are passed daily. The paired kidneys are responsible for the formation of urine and its excretion (diuresis). Diseases such as diabetes mellitus can cause the average volume of urine to increase many times over.
What is urinary output?
Urine temporal volume (also urinary temporal volume) includes the amount of urine excreted in a specified period of time. With the excretion of urine, the kidneys detoxify the body. At the same time, they thus contribute to the regulation of the water and electrolyte balance. Urine formation proceeds in three steps. First, the so-called primary urine is filtered by the work of the kidneys. This is done by the renal corpuscles. Primary urine is an almost protein-free, unconcentrated ultrafiltrate that is produced when the kidneys are perfused. A total of 180 to 200 liters of primary urine are produced daily by the two kidneys. This comes from the 1500 to 1800 liters of blood that flow through the kidneys every day. Around 300 times a day, a person’s entire blood volume flows through the kidneys. The composition of primary urine is comparable to that of blood plasma. The difference is essentially only that larger blood components are intercepted by the vessels before they can be processed by the kidneys. The primary urine then passes through the renal tubules, where it is reabsorbed and secreted. Protein, electrolytes, glucose and water are absorbed, resulting in the secondary urine. About 19 liters of it are formed per day. Then these quantities of fluid are further concentrated and finally pass through the renal pelvis and ureters into the urinary bladder, from where they are excreted as urine. Every day, this amounts to 1.5 to two liters. Thus, the urine time volume is reached.
Function and task
Diuresis can fluctuate and in this context respond to external factors. Under cold stress, diuresis increases in intensity. Reduced atmospheric pressure has a similar effect above an altitude of 3000 meters. Numerous active substances in food also influence urine excretion. Caffeine, for example, increases diuretic activity. The same applies to alcohol. Both substances suppress the production of the hormone ADH (antidiuretic hormone), which helps the kidneys to reflux water from the urine. However, when coffee is consumed in large quantities over long periods of time, urine excretion stabilizes again at a lower level. Medicine makes use of the principle of diuresis by stimulating increased urine excretion with special preparations in order to reduce the burden on the circulatory system. Increased urine volume indirectly reduces the volume of blood and thus the load on the heart. This effect helps patients with kidney and circulatory diseases in particular. Diuretic drugs are also used in cases of poisoning. Water-soluble toxins are flushed out of the body in this way. Controlling the volume of urine is therefore one of the preferred treatment methods, especially in intensive care medicine. Diabetes patients, on the other hand, often have a significantly excessive urine output, which is why medication is usually used here as well. Increased urine production by the kidneys due to increased pressure in the urinary tract is called osmotic (water-drawing) diuresis. These processes are based on the retention of osmotically active substances in the tubules (tubes) of the kidneys. They are not returned to the blood after filtration. In order to maintain the concentration of the substances concerned at the required level, more water flows passively into the urine to be excreted (polyuria). At the same time, this inspires drinking. Osmotic diuresis can be induced artificially by administration of appropriate drugs to treat emergencies such as glaucoma, cerebral edema, or acute renal failure.
Diseases and medical conditions
Thanks to its pH value, urine allows sound conclusions to be drawn about a person’s nutrition. For this measurement, the urine time volume is used as a basis in the sense of reliable results. With a normal diet, the pH of the urine ranges between 4.6 and 7.5. It is thus in the acidic range.A protein-rich diet shifts the pH value even more strongly into the acidic environment. A high consumption of vegetables, on the other hand, tends to shift the pH into the alkaline range. The so-called urine status can indicate diseases of the kidneys (kidney stones, kidney tumor) and inflammations of the urinary tract in the early stages. Metabolic diseases such as diabetes mellitus and liver weakness are also indicated in this way. If, for example, proteins, nitrite, ketones and blood components can be found in the urine, this indicates various possible diseases. Nephrology, a branch of internal medicine, and urology, which is mainly responsible for surgical issues, deal specifically with kidney diseases. These are very diverse fields of activity, because in addition to excreting the final products of metabolism, the kidneys are also responsible for balancing the body’s water balance, regulating blood pressure over the long term, and controlling the acid-base balance. The pH value of the blood, for example, which is significantly influenced by kidney activity, may only fluctuate within a relatively narrow range, otherwise life-threatening conditions may occur. Here, too, the measured and recorded urine volume provides important information. It further provides information about the synthesis of glucose that occurs in the kidneys, their hormone production, and the concomitant breakdown of hormones such as peptides.
