Dehydration occurs when a person loses more bodily fluid than he or she takes in. It can happen gradually over a period of time, or very quickly in some cases due to extreme exercising. Two thirds of the human body is made up of water. When dehydration occurs, it means a person has lost a sufficient amount of fluid for the body to stop working normally.
A small loss of fluid does not normally effect the body's system and can go unnoticed. If dehydration is allowed to continue, then problems will arise. The first symptom of dehydration may be a dry or sticky mouth. You may also feel dizzy and suffer from nausea. You will also notice that your urine has become darker, and you may produce less.
There are many common causes of dehydration. You can suffer from severe dehydration when you become ill. Stomach bugs, diarrhea and the common cold can all lead to the body losing fluid. If you are ill and have a fever or vomit, then fluid will be lost. If you have been using laxatives or diuretics, this can also account for a loss of fluid.
During sports, people sweat continuously and should top up their fluids at regular intervals. When people sweat, they are also losing valuable minerals such as salt and potassium.
Dieting is also another case in which dehydration can occur. Many dieting aids cause fluid to be lost from the body as a quick way to reduce weight. Losing water will not help you to shed fat; it will only make you feel ill.
Dehydration occurs when there isn't enough water to replace what's lost throughout the day. Your system literally dries out. Sometimes dehydration occurs for simple reasons: You don't drink enough because you're sick or busy, or because you lack access to safe drinking water when you're traveling, hiking or camping.
Other dehydration causes include:
Diarrhea, vomiting. Severe, acute diarrhea — that is, diarrhea that comes on suddenly and violently — can cause a tremendous loss of water and electrolytes in a short amount of time. If you have vomiting along with diarrhea, you lose even more fluids and minerals. Children and infants are especially at risk.
Fever. In general, the higher your fever, the more dehydrated you may become. If you have a fever in addition to diarrhea and vomiting, you lose even more fluids.
Excessive sweating. You lose water when you sweat. If you do vigorous activity and don't replace fluids as you go along, you can become dehydrated. Hot, humid weather increases the amount you sweat and the amount of fluid you lose. But you can also become dehydrated in winter if you don't replace lost fluids. Preteens and teens who participate in sports may be especially susceptible, both because of their body weight, which is generally lower than that of adults, and because they may not be experienced enough to know the warning signs of dehydration.
Increased urination. This is most often the result of undiagnosed or uncontrolled diabetes mellitus, a disease that affects the way your body uses blood sugar. This type of diabetes often causes increased thirst and more frequent urination. Another type of diabetes, diabetes insipidus, also is characterized by excessive thirst and urination, but in this case the cause is a hormonal disorder that makes your kidneys unable to conserve water. Certain medications — diuretics, antihistamines, blood pressure medications and some psychiatric drugs — as well as alcohol also can lead to dehydration, generally because they cause you to urinate or perspire more than normal.
Depending on how much of your body weight is lost through fluids, dehydration can be described as mild, moderate or severe.
The first sign of dehydration is thirst. Other symptoms may include:
dizziness or light-headedness
headache
tiredness
dry mouth, lips and eyes
concentrated urine (dark yellow)
passing only small amounts of urine infrequently (less than three or four times a day)
Moderate dehydration causes you to lose strength and stamina. It's the primary cause of heat exhaustion. You should be able to reverse mild to moderate dehydration by drinking more fluids, without medical attention.
If dehydration is ongoing (chronic), it can affect your kidney function and cause kidney stones to develop. It can also cause:
liver, joint and muscle damage
cholesterol problems
constipation
Untreated mild or moderate dehydration can lead to severe dehydration.
Severe dehydration is a medical emergency and requires immediate medical attention. You should seek medical attention if you or your child has any of the following symptoms:
dry, wrinkled skin that sags slowly into position when pinched up
an inability to urinate, or not passing urine for eight hours
irritability
sunken eyes
low blood pressure (hypotension)
a weak pulse
a rapid heartbeat
cool hands and feet
fits (seizures)
a low level of consciousness
feeling tired (lethargic) or confused
blood in your stools (faeces) or vomit
If not treated immediately, severe dehydration can lead to complications. You can even die from severe dehydration because the blood stops circulating. If you experience this level of dehydration, you may need to be admitted to hospital and be put on a drip to restore the substantial loss of fluids.
You should visit your GP if your symptoms continue, despite drinking plenty of fluids or if you suspect that your baby or toddler is dehydrated.
If your doctor suspects dehydration, you may be given a blood test or a urine test to check the balance of salts (sodium and potassium) in your body.
Contact your GP or out-of-hours service straight away if you have any of the following symptoms:
feeling tired (lethargic) or confused
dry mouth and eyes that don't produce tears
not passing urine for eight hours
dry skin that sags slowly into position when pinched up
rapid heartbeat
blood in your stools (faeces) or vomit
low blood pressure (hypotension)
Also contact your GP if you or your child has diarrhoea that lasts longer than five days, or vomiting that lasts more than 24 hours in adults or 12 hours in a child.
In the early stages, you may be able to correct mild to moderate dehydration with home treatment measures. It is important to control fluid losses and replace lost fluids.
If you become mildly to moderately dehydrated while working outside or exercising:
Stop your activity and rest.
Get out of direct sunlight and lie down in a cool spot, such as in the shade or an air-conditioned area.
Prop up your feet.
Take off any extra clothes.
Drink a rehydration drink, water, juice, or sports drink to replace fluids and minerals. Drink 2 qt (2 L) of cool liquids over the next 2 to 4 hours. You should drink at least 10 glasses of liquid a day to replace lost fluids. You can make an inexpensive rehydration drink at home. But do not give this homemade drink to children younger than 12. Measure all ingredients precisely. Small variations can make the drink less effective or even harmful. Mix the following:
1 quart (950 mL) water
½ teaspoon (2.5 g) baking soda
½ teaspoon (2.5 g) table salt
¼ teaspoon (1.25 g) salt substitute (potassium-based), such as Lite Salt or Morton Salt Substitute
2 tablespoons (30 g) sugar
Rest and take it easy for 24 hours, and continue to drink a lot of fluids. Although you will probably start feeling better within just a few hours, it may take as long as a day and a half to completely replace the fluid that you lost.
Make sure your child is drinking often. Frequent, small amounts work best.
For children with dehydration, an oral rehydration solution (ORS), half-strength orange juice, or plain water (if the child is eating food) may be used to replace lost fluids.
Allow your child to drink as much fluid as he or she wants. Encourage your child to drink extra fluids or suck on Popsicles. Children ages 4 to 10 should drink at least 6 to 10 glasses of liquids to replace lost fluids.
Cereal mixed with milk or water may also be used to replace lost fluids.
Don't wait until dehydration develops to replace lost fluids. Offer fluids to your baby often.
If you breast-feed your baby, nurse him or her more often.
If you use a bottle to feed your baby, the amount of fluid you normally use in the formula should be enough to replace lost fluids. Check with your child's doctor if you think you need to feed your baby more often.
Use an oral rehydration solution (ORS) if mild or moderate dehydration develops. The amount of ORS your baby needs depends on his or her weight and how dehydrated he or she is. You can give the ORS in a dropper, spoon, or bottle.
If your baby has started eating cereal, you may replace lost fluids with cereal. You also may feed your baby strained bananas and mashed potatoes if your child has had these foods before.
Use the Check Your Symptoms section to evaluate the symptoms if any of the following occur during home treatment:
More serious dehydration develops.
Decreased alertness develops.
You become dizzy, lightheaded, or feel like you might faint when you rise from lying to sitting, or from sitting to standing.
Decreased urination develops.
Symptoms become more severe or frequent.