What is Dehydration?
Dehydration happens when fluid loss from the body exceeds intake. Water is essential for life and makes up about 60 percent of our body weight.
Water acts as a building material in the body and is a vital nutrient for every cell. Along with respiration it helps regulate body temperature by sweating. Essential foods like carbohydrates and proteins are carried around by water in the bloodstream.
Water also helps flush away waste, lubricates joints, produces saliva and acts as a shock absorber for our central nervous system. (1)
Consequently it becomes obvious that dehydration has a major impact on many bodily functions.
On average, an adult male needs about three liters of water a day and a woman just over two. This can be obtained from both fluids that we drink and food that we eat. (2)
When we don’t ingest enough fluid there are symptoms that can warn us we are dehydrated and these include:
One sign that you are dehydrated might be that you feel extreme thirst. This is not always a reliable indication though as you can be dehydrated and not feel thirsty. (3)
Saliva production helps keep our mouth and throat lubricated. It is also important for talking, chewing swallowing and tasting.
When we don’t get enough fluids saliva production slows and the mouth becomes dry. (4)
Depletion of fluid levels in the body can make you feel tired and weak. You might feel very lethargic and lack the energy to carry out even menial tasks. (5)
Dehydration affects our urine in a couple of ways. Firstly in the amount we urinate and secondly in its appearance.
The kidneys are responsible for regulating the balance of fluid in our body. They require water to filter waste from the bloodstream and produce urine to remove this waste.
When dehydrated the brain sends signals to the kidneys which in turn reduces urine output to conserve water in the body. (6)
The other factor when it comes to urine is its color, the darker the urine the more dehydrated the body. Urine should be pale or clear, when it starts getting darker, and also smelling stronger, the chances are your body is lacking fluids. (7)
Depriving the body of water can lead to headaches and lack of concentration. This could be due to reduced water around the brain. Rehydrating can relieve this headache in about 30 mins to 3 hours. (8)
Often people with dehydration feel dizzy, this could be due to a drop in blood pressure. (9)
The skin is one of the largest organs in the body and it’s water content is about 30 percent. Water contributes to keeping the skin elastic, plump and resilient as well as helping retain moisture.
When dehydrated the moisture loss in the skin can be seen. When it is pinched it will take a short while to return to its normal position. (10)
Tear fluid helps keep our eyes moist and hydrated. When fluid levels in the body are low tear production is impaired, particularly in children. (11)
Some aspects such as concentration, short term memory and alertness can be affected by dehydration. This is especially the case in children, young adults and older adults.
It impairs their ability to perform fine motor skills and deal with arithmetical type problems. It can also interfere with vision and sensory responses. (12)
Symptoms in Children
Symptoms in children can vary slightly and include vomiting, diarrhea as well as lower urination. They will eat and drink less instead of keeping up with fluid losses. Very young children will not be able to express their feelings, so as parents, close attention needs to be paid to symptoms.
Children can become increasingly lethargic and may go into hypovolemic shock if they lose too much body fluid. (13)
Symptoms in the Elderly
Older people will often not realise they are dehydrated, so again, carers or family should pay close attention to symptoms to avoid complications.
Stages of dehydration are measured depending on the degree the person is dehydrated. These are symptom based and categorized as mild, moderate and severe. (14)
This applies to fluid loss of between three and five percent of body weight. It is likely thirst will be the only symptom displayed.
Loss of body fluids in this category are between six and 10 percent of body weight. Mental status will be listless and irritable, and heart rate will increase but blood pressure will be normal.
A person’s pulse will be harder to detect and breathing tends to be irregular and rapid. Urine output will be less than normal. If the skin is pressed it may take longer than two seconds to return to normal color.
In babies the fontanelle, the space between the bones in the skull which have not closed, might be sunken. In infants and young children the eyes can appear sunken.
Loss of body fluids in this category will be at more than 10 percent of body weight. Mental status will be noticeably altered and heart rate will be increased. Blood pressure will have decreased and be low.
A person’s pulse will be weak and hard to find and breathing can be abnormal and rapid. Urine output will be below 1 ml per kg per hour in infants, under 0.5 ml per kg per hour in children, and less than 400 ml to 500ml per 24 hours in adults.
Depressing the skin will take longer than two seconds to return to normal color and tear production will be reduced.
As with mild or moderate dehydration, the eyes in infants and children will be sunken, as will the fontanelle in babies.
The aim of treatment for dehydration is to return fluid levels to normal. There are two methods by which this can be done.
Patients who are able to should sit up and drink water with oral rehydration salts (ORS) added straight away. They should be encouraged to drink but not fluids like soft drinks, sports drinks or juices.
ORS should be drunk frequently and monitored against fluid loss through diarrhea or vomiting.
However, if a patient is vomiting regularly ORS can be administered via a nasal tube to the stomach.
An approximation of how much ORS is needed for older children and adults is 100ml every five minutes.
A more accurate calculation is to multiply a person’s weight in kg by 75 and administer that amount of rehydration salts in millilitres every four hours. For example, someone weighing 60 kg x 75 = 4500 ml every four hours.
If someone wants to drink more, they should be allowed to. Once stabilized, a normal diet can be resumed.
If an infant is being breastfed they should continue to do so.
Someone who is severely dehydrated may not be able to take fluids orally, therefore fluids will be given via an intravenous drip. This could be because they are in a coma, vomiting uncontrollably or extremely fatigued.
Again it is important to measure the amount of fluid intake is against what is lost. ORS can be administered by mouth alongside a drip as soon as a person is able.
As soon as fluid hydration levels have improved, oral or nasal methods will replace intravenous intervention. (15)
What is dehydration? Dehydration happens when fluid loss from the body exceeds fluid intake.
What are the signs of dehydration? There are many indications that you might be dehydrated. They include thirst, tiredness, dry mouth, decreased urination, dark urine and headache.
How do you develop dehydration? Dehydration happens when you don’t get enough fluids to replace those lost from your body. This could be as a result of exercise or just not drinking enough water. Some diseases and their treatments, like cancer or illness, sickness and diarrhea, can also make you dehydrated.
How are you diagnosed for dehydration? A doctor will check your vital signs including, pulse, blood pressure and temperature. They might also do blood and urine tests to check the level of dehydration and find the cause. (16)
What is the best treatment for dehydration? The main priority for dehydration is to replace lost fluids. This can be done by administering rehydration salts in water or intravenously.
What are the long term complications of dehydration? If untreated dehydration can lead to heat stroke, heat exhaustion, permanent brain damage, seizures and death. (17)
Is dehydration considered a disability? No, dehydration isn’t considered a disability. Most people experiencing dehydration will fully recover once rehydrated.
Is there a cure for dehydration? As we have just mentioned recovery from dehydration has a good prognosis.
Is dehydration life threatening? Untreated, yes, dehydration can be life threatening.
Dehydration happens when fluid loss from the body exceeds fluid intake and if not treated swiftly, can be serious.
Many things can cause dehydration, however the good news is that rehydration is usually successful and symptoms abate.
Dehydration in children and the elderly needs prompt attention because they can lose fluids quickly which can lead to serious complications.