How much water do you need in a day

The exact amount varies with every individual including your health, and activity.  .

Health benefits of water

Water is your body’s principal chemical component, comprising, on average, 60 percent of your weight. Every system in your body depends on water. For example, water flushes toxins out of vital organs, carries nutrients to your cells and provides a moist environment for ear, nose and throat tissues.

Lack of water can lead to dehydration, a condition that occurs when you don’t have enough water in your body to carry out normal functions.

How much water do you need?

Every day you lose water through your breath, perspiration, urine and bowel movements. For your body to function properly, you must replenish its water supply by consuming beverages and foods that contain water.

A couple of approaches attempt to approximate water needs for the average, healthy adult living in a temperate climate.

• Replacement approach. The average urine output for adults is 1.5 liters a day. You lose close to an additional liter of water a day through breathing, sweating and bowel movements. Food usually accounts for 20 percent of your total fluid intake, so if you consume 2 liters of water or other beverages a day (a little more than 8 cups) along with your normal diet, you will typically replace the lost fluids.
• Dietary recommendations. The Institute of Medicine advises that men consume roughly 3.0 liters (about 13 cups) of total beverages a day and women consume 2.2 liters (about 9 cups) of total beverages a day.

Even apart from the above approaches, it is generally the case that if you drink enough fluid so that you rarely feel thirsty and produce between one and two liters of colorless or slightly yellow urine a day, your fluid intake is probably adequate.

Signs and symptoms of dehydration include:

• Mild to excessive thirst
• Fatigue
• Headache
• Dry mouth
• Little or no urination
• Muscle weakness
• Dizziness
• Lightheadedness

Mild dehydration rarely results in complications — as long as the fluid is replaced quickly — but more-severe cases can be life-threatening, especially in the very young and the elderly. In extreme situations, fluids or electrolytes may need to be delivered intravenously.