The human body is roughly 75 percent water. Without this water, it cannot survive. Water is found inside cells, within blood vessels, and between cells.

A sophisticated water management system keeps our water levels balanced, and our thirst mechanism tells us when we need to increase fluid intake.

Although water is constantly lost throughout the day as we breathe, sweat, urinate, and defecate, we can replenish the water in our body by drinking fluids. The body can also move water around to areas where it is needed most if dehydration begins to occur.

Most occurrences of dehydration can be easily reversed by increasing fluid intake, but severe cases of dehydration require immediate medical attention.

The first symptoms of dehydration include thirst, darker urine, and decreased urine production. In fact, urine color is one of the best indicators of a person’s hydration level – clear urine means you are well hydrated and darker urine means you are dehydrated.

However, it is important to note that, particularly in older adults, dehydration can occur without thirst. This is why it is important to drink more water when ill, or during hotter weather.

As the condition progresses to moderate dehydration, symptoms include:

• dry mouth
• lethargy
• weakness in muscles
• headache
• dizziness

Severe dehydration (loss of 10-15 percent of the body’s water) may be characterized by extreme versions of the symptoms above as well as:

• lack of sweating
• sunken eyes
• shriveled and dry skin
• low blood pressure
• increased heart rate
• fever
• delirium
• unconsciousness

Symptoms in children

• in babies – a sunken fontanel (soft spot on the top of the head)
• dry tongue and mouth
• irritable
• no tears when crying
• sunken cheeks and/or eyes
• no wet diaper for 3 or more hour