Our body loses water every day through the body's activities during the day. If the water that has been lost is not re-fueled, the body becomes dehydrated. The thirst mechanism start when we have lost between 1 and 2 percent of body water. However, it is often mistaken for hunger. If we ignore it, the dehydration will continue and seriously affects both mental and physical performance. 3 percent loss of body water can result in loss of muscle strength. That is why we feel weak and tired.

Mild dehydration can lead to constipation, headaches, lethargy and mental confusion. The body temperature goes up and concentration becomes more difficult. Tiredness in the afternoon are mostly resulted from mild dehydration.

Ask yourself these questions to see if your body needs more water.

•  Do you often have constipation?
• Are you often thirsty? ( If you're constantly thirsty, it can mean that you need more water, or something else. The other two reasons are diabetes, and essential fat deficiency, which often happen to children)
• Do you have joint problems?
• Do you feel tired?
• Do you have difficulty concentrating, dizziness, or lightheaded?
• Are you overheating?
• Are you having dry skin, mouth, or lips?
• Do you get frequent infections?
• Are you having dry, brittle hair?
• Does your urine has very strong, dark yellow color?
  
  
  

8 glasses per day are approximately 2 quarts a day. Even though we all need water but the amount that we need could be varied, depending on each person's condition. Just like nutrients, each person has different needs. There is no universal rule for this. A good estimate is to take your body weight in pounds and divide that number in half. ( For example, if your are 150 pounds. You need at least 75 ounces of water per day) That gives you the number of ounces of water per day that you need to drink.

Other factors to consider include physical activities (If you work out, you should drink more because of sweating), climate ( Dry or humid), health condition ( If need to limit water intake), and physical condition (Women who are expecting or breast-feeding need additional fluids to stay hydrated.)

Water intoxication and hyponatremia

 It is possible, but very rare to happen. Most people are drinking water less than drinking too much. Drinking a large amount of water in a short period of time can lead to water intoxication. It simply said that the person is 'drown' in water that has been drunk. Too much water leads to the dilution of sodium in the body. Drinking an enormous amount of water also overwhelms the kidneys as they can't process and eliminate the water fast enough, so the amount of sodium in your blood drops too low. This is a disorder called 'hyponatremia' which means 'low sodium' . The brain needs sodium to function properly. When the sodium levels drop, a person feels confusion and lethargy. Severe symptoms can lead to twitching, seizures and even death. Water intoxication and hyponatremia result when a dehydrated person drink too much water without the accompanying electrolytes. 

This condition is most commonly seen in infants under six months and sometimes in athletes. A baby can get water intoxication if drank many bottles of water a day. (Which rarely happens) Athletes lose water by sweating heavily, so they lose both water and electrolytes (Salt / Sodium). Drinking too much water will likely lead to hyponatremia as mentioned above.

Some other factors that can trigger the thirst reflex the body includes some drugs and psychological disorder, makes the person can't stop drinking.

 So, It is not how much you drink, it is how fast you drink it.

Twenty percent of your water need will come from the foods you eat. The rest of your water need should come from the beverages you drink. Water is the best choice. Drinking small amounts of water throughout your day is better than drinking many glasses of water in a short time. As you can see that water intoxication is a very rare condition. So even if you drink a little more than you need per day but in a small amount throughout your day should not do any harm to your body.