What are the signs and symptoms of dehydration?

Thirst, dry mouth, decreased urine output, and dizziness are hallmark signs and symptoms of dehydration. When the body loses more fluids than it takes in, it triggers a response that includes increasing thirst to encourage fluid intake. A dry mouth occurs due to reduced saliva production, which is a direct consequence of fluid loss. Decreased urine output is a classic indication that the kidneys are conserving water in response to dehydration, leading to more concentrated urine. Dizziness can occur as a result of decreased blood volume and blood pressure, which affects cerebral perfusion.

In contrast, an increased appetite and weight gain are not associated with dehydration. Typically, dehydration leads to a decreased appetite. Fatigue and excessive sweating can be manifestations of many health conditions and are not specific to dehydration. Flushed skin and rapid heartbeat may occur during dehydration but are generally not primary indicators. Therefore, the combination of thirst, dry mouth, decreased urine output, and dizziness distinctly characterizes dehydration.