What you should know about dehydration

DEHYDRATION occurs when
more water and fluids leave the
body than enter it. Even low levels

of dehydration can cause head-
aches, lethargy, and constipation.

The human body is roughly 75
percent water. Without this water,
it cannot survive. Water is found
inside cells, within blood vessels,
and between cells.

A sophisticated water manage-
ment system keeps our water levels

balanced, and our thirst mechanism
tells us when we need to increase
fluid intake.

Although water is constantly lost
throughout the day as we breathe,
sweat, urinate, and defecate, we
can replenish the water in our body
by drinking fluids. The body can
also move water around to areas

where it is needed most if dehydra-
tion begins to occur.

Most occurrences of dehydration

can be easily reversed by increas-
ing fluid intake, but severe cases

of dehydration require immediate
medical attention.
Fast facts about dehydration
•Around three-quarters of the
human body is water.
•The causes of dehydration
include diarrhea, vomiting, and
sweating.

•Individuals more at risk of dehy-
dration include athletes, people at

higher altitudes, and older adults.
•Early symptoms of dehydration
include dry mouth, lethargy, and
dizziness.
Symptoms of dehydration
Water depletion

Dehydration is easy to rem-
edy but can be serious if left

unchecked. The first symptoms of
dehydration include thirst, darker

urine, and decreased urine produc-
tion. In fact, urine colour is one of

the best indicators of a person’s hydration level – clear urine means
you are well hydrated and darker
urine means you are dehydrated.
However, it is important to note
that, particularly in older adults, de- hydration can occur without thirst.
This is why it is important to drink
more water when ill, or during hot- ter weather.
As the condition progresses to
moderate dehydration, symptoms
include:
•dry mouth
•lethargy
•weakness in muscles
•headache
•dizziness
Severe dehydration (loss of 10-15
percent of the body’s water) may be
characterized by extreme versions
of the symptoms above as well as:
•lack of sweating
•sunken eyes
•shriveled and dry skin
•low blood pressure
•increased heart rate
•fever
•delirium
•unconsciousness
Symptoms in children
•in babies – a sunken fontanel
(soft spot on the top of the head)
•dry tongue and mouth
•irritable
•no tears when crying
•sunken cheeks and/or eyes
•no wet diaper for 3 or more
hours
Causes of dehydration

The basic causes of dehydra-
tion are not taking in enough

water, losing too much water, or a
combination of both. Sometimes, it
is not possible to consume enough
fluids because we are too busy, lack
the facilities or strength to drink,
or are in an area without potable
water (while hiking or camping, for example).
Additional causes of dehydration include:

(a) Diarrhea – the most common cause of de-
hydration and related deaths. The large intestine

absorbs water from food matter, and diarrhea
prevents this from happening. The body excretes
too much water, leading to dehydration.
(b) Vomiting – leads to a loss of fluids and makes
it difficult to replace water by drinking it.
(c) Sweating – the body’s cooling mechanism
releases a significant amount of water. Hot and
humid weather and vigorous physical activity can

further increase fluid loss from sweating. Simi-
larly, a fever can cause an increase in sweating and

may dehydrate the patient, especially if there is
also diarrhea and vomiting.
(d) Diabetes – high blood sugar levels cause
increased urination and fluid loss.

(e) Frequent urination – usually caused by un-
controlled diabetes, but also can be due to alcohol

and medications such as diuretics, antihistamines,
blood pressure medications, and antipsychotics.
(f) Burns – blood vessels can become damaged,
causing fluid to leak into the surrounding tissues.

Risk factors for dehydration

Although dehydration can happen to
anyone, some people are at a greater
risk. Those at most risk include:
•People at higher altitudes.
•Athletes, especially those in endur- ance events, such as marathons, triath- lons, and cycling tournaments. Dehy- dration can undermine performance in
sports, as this article explains.
•People with chronic illnesses, such
as diabetes, kidney disease, cystic
fibrosis, alcoholism, and adrenal gland
disorders.

•Infants and children – most common-
ly due to diarrhea and vomiting.

Dehydration in older adults is also
common; sometimes this occurs
because they drink less water so that
they do not need to get up for the toilet
as often. There are also changes in
the brain meaning that thirst does not
always occur.
Complications of dehydration
If dehydration is not checked, it can
lead to serious complications. These can
include:
(a) Low blood volume – less blood
produces a drop in blood pressure and
a reduction in the amount of oxygen

reaching tissues; this can be life threat-
ening.

(b) Seizures – due to an imbalance of
electrolytes.

eventually kidney failure.
(d) Heat injury – ranging from mild
cramps to heat exhaustion or even heat
stroke.