Mild cases of dehydration are a pretty common occurrence and aren't anything to get too worked up about. Very often the minor symptoms associated with mild dehydration such as headaches and irritability can be alleviated with a glass or two of water. There is a debate in the health community that deals with the recommendation of eight glasses of water a day for healthy living. The truth is that we can get almost that much liquid from ordinary dietary ingestion, i.e., having something to drink with a meal. However, if you are an active individual or it is excessively warm where you live, your liquid intake needs to be increased to compensate for perspiration. Usually people don't notice dehydration until it turns into heat exhaustion. If things get that bad for you, then you need to start worrying. Severe dehydration is no joke—it can definitely kill you.
Prevent dehydration, if you can. As adults, we process through quite a lot of water on a daily basis. This varies a bit by gender and a lot by activity level, but an average figure is somewhere around 2‒4 liters. This is lost through perspiration, respiration, and urination. This number is related to the recommendation of eight glasses of water a day—two liters is around eight and a half cups. If you feel thirsty, drink water. If it is hot and you are more active, drink more. If you're not urinating every couple of hours, drink even more.
Lower body temperature to reduce perspiration. If you or someone you know is experiencing some of the symptoms of dehydration and it is more than just feeling thirsty for a cold one, then you need to take some additional steps. It is possible that the subject is experiencing dehydration-caused heat exhaustion, which can lead to a deadly heat stroke. The first step is to get out of the hot environment. Find shade or, better yet, a fan or air conditioning. Apply a cold compress to the forehead, neck, and armpits. This will reduce fluid loss via sweating and cool the body temperature down.
Elevate feet to improve blood circulation. Part of being dehydrated is a state called hypovolemia or volume contraction, in which the volume of blood in the body is reduced. Some signs of this are an increased heart rate, low blood pressure, turning pale, dizziness, feeling faint, nausea, confusion, decreased urine output, sweating with cool pale skin, and extreme thirstiness. Laying the subject down and elevating the legs will help keep the blood flow centered on the core of the body and the head. This will help reduce circulatory shock and potentially decrease body temperature as well.
Drink fluids to replenish body liquids. As stated above, a lot of minor dehydration symptoms can be alleviated with a glass or two of water. But it is also possible that you have depleted your body's electrolytes in the process. Electrolytes are excreted when we sweat, and they are basically different kinds of salts needed for proper muscle and nerve functionality. Sports drinks contain electrolytes, as do many foods. There is a recipe for an electrolyte drink in the sidebar of this article. Remember, the rate of rehydration for mild dehydration is five teaspoons of liquid per pound of body weight over four hours.
Serious dehydration requires hospitalization. It is possible that the subject is beyond the point where oral rehydration therapy can make up for the loss of bodily liquids. In fact, sometimes drinking too many liquids when you're dehydrated can be dangerous, leading to a cerebral edema. Some signs of serious dehydration include lethargy, loss of consciousness, seizures, and sunken eyes. If you suspect or have observed that the dehydration is at this level, you need to get the subject to an emergency room or call an ambulance immediately. They will be able to evaluate their needs, provide intravenous saline fluids, and monitor their condition.
Generally speaking, dehydration is caused by a reduction of liquids in one's body. You might be picturing a trip through the desert on a nameless horse, but it could just as well happen in the safety of your own home. Dehydration could be caused by overdoing it on the treadmill, prolonged exposure to a dry environment, blood loss, diarrhea, hyperthermia, shock, vomiting, burns, excessive tears, drug or alcohol use, diseases like cholera, yellow fever, shigellosis, diabetes, food borne illness, or fasting.