Which of the following is a common cause of oliguria?

Oliguria, defined as a reduced urine output, can often be attributed to dehydration. When the body experiences dehydration, there is a decrease in blood volume, leading to reduced kidney perfusion. The kidneys respond to this reduced blood flow by conserving water, which results in less urine being produced. Dehydration can occur due to various factors such as inadequate fluid intake, excessive fluid loss through vomiting, diarrhea, or sweating. This relationship between dehydration and oliguria underscores why dehydration is recognized as a common cause of decreased urine output.

In contrast, while excessive exercise can lead to fluid loss and potentially contribute to dehydration, it is not commonly recognized as a direct cause of oliguria, as physical activity may also promote kidney function. A high fiber diet is typically beneficial for overall health and does not directly lead to decreased urine output. Skin disorders may change fluid balance but are not directly linked to oliguria. Hence, dehydration is the most recognized and common cause among the given options.