How can dehydration influence urine concentration?

Dehydration significantly impacts urine concentration by causing the kidneys to conserve water. When the body is dehydrated, it sends signals to the kidneys to reabsorb more water back into the bloodstream. This process occurs because the body is trying to maintain its fluid balance and prevent further loss of water. As a result, the urine that is produced becomes more concentrated due to the higher reabsorption rate of water.

The kidneys achieve this by releasing an antidiuretic hormone (ADH), which increases the permeability of the kidney tubules, allowing more water to be absorbed. Consequently, the final product is a smaller volume of urine that is highly concentrated with waste products and solutes, reflecting the body’s effort to retain as much water as possible during periods of dehydration. This physiological response ensures that the body can survive even when fluid intake is low.