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Hydration
By
Dr. Virginia
Cummings |
Question: How
can I keep from getting dehydrated in the hot summer
weather?
Answer: Dehydration is a common problem, and not
just in the summer! Senior citizens are especially at risk
for dehydration for a number of reasons, so it is important
that they be aware of the risk factors for and symptoms of
dehydration.
Dehydration occurs when the body loses water. Water is
present in three ways in the body – in each individual cell,
circulating in our arteries and veins as plasma (which, when
mixed with red and white cells is then known as “blood”) and
outside the cells in body tissues (this is known as the
“third space”). When the body loses water, it loses it from
all three spaces. But, since the water in plasma (or blood)
is the most important of the three, the body’s coping
mechanisms tend to try to get water into the plasma from the
other two places.
Unfortunately, water in the tissue, or the “third space” is
hard for the body to access and recover, so the body draws
water from its cells into the plasma, to make sure that
circulation can continue. This leads to impairment in cell
functioning. Among the most vulnerable cells are the brain,
kidney and GI tract cells that are pretty important to our
existence!
There are two types of dehydration: loss of water alone and
loss of salts and water. The first type, loss of water
without significant salt loss occurs most commonly from
sweating. Although sweat contains some sodium, or salt, it
is primarily water. If a person sweats more water than they
take in, they will be come dehydrated. Remember that
sweating does not just occur in the heat! Fever is one of
the most common causes of this type of dehydration, since it
causes excess sweating.
If the sodium of a person with this type of dehydration is
measured, it will be high, since the measurement looks at
the ratio of sodium to water in the plasma. A high sodium
level will stimulate the thirst center of the brain, to make
the person thirsty. Thirst is one of the symptoms of
dehydration. Unfortunately, that thirst center becomes less
sensitive to high sodium with aging, which is reason #1 that
seniors are at risk for dehydration. They may not feel
thirsty and want to drink, even if the ratio of sodium to
water in the body is abnormally high.
Other signs and symptoms of dehydration include dizziness,
rapid heart rate and low blood pressure, which all occur
because the body has lost water in the plasma and the body’s
circulation is suffering. Headache may occur as the cells in
the brain lose water; nausea and vomiting from loss of water
to the cells in the intestines and weakness and fatigue from
loss of water in muscle cells.
Additionally, the kidneys will try to preserve water and
will concentrate the urine, which may then appear dark
colored and will be decreased in amount. The skin may appear
dry and lose some of its elasticity as water is lost from
the tissue. In its most severe form, dehydration can lead to
death from seizure or heart attack and circulatory collapse.
The treatment for this type of dehydration is water, water,
water! Fortunately for our taste buds, most fluids contain
primarily water, and can be substituted for plain water to
keep hydrated. Two major exceptions to this are ALCOHOL and
CAFFEINATED BEVERAGES. Alcohol and caffeine actually
stimulate the brain to produce a hormone which tells the
kidneys to get rid of water, even if the body is already
dehydrated. So coffee, tea and alcoholic drinks only make
the situation worse! Stick to water, juice, milk, even sodas
(if decaffeinated). Also, fruits and vegetables with high
water content are good, such as melon, peaches, lettuce and
cucumbers.
How much water does the body need per day? A good estimate
is to take the weight in pounds (no cheating!), divide by
two and try to take in that many ounces of water per day in
foods and beverages. Increase the amount of water in
situations that may lead to increased sweating, such as
fever, heat and a very dry environment.
The second type of dehydration involves loss of body salts
such as sodium, potassium and magnesium, as well as water.
This occurs with vomiting, diarrhea and bleeding. Replacing
these types of losses with water alone only solves half the
problem. The salts need to be replaced as well. In this type
of dehydration, the sodium in the plasma may be low. The
person may not feel thirsty and may get profoundly
dehydrated.
One of the most common scenarios for this type of
dehydration occurs when a person is taking diuretic
medications, for high blood pressure or heart disease. These
stimulate the kidneys to excrete salt and water. This leads
to a chronic state of mild dehydration, which can quickly
become severe if a GI virus or a fever occurs. Seniors are
more likely to be on this type of medication than young
people; this is reason #2 that seniors are at increased risk
for dehydration.
The treatment for this type of dehydration is water AND
salt. Fluids like soup and Gatorade or other sports drinks
can help, or in severe cases, IV fluids containing salt and
water may be necessary. If the signs and symptoms of
dehydration occur after vomiting or diarrhea, or while on
diuretic medication such as lasix, bumex, hydrochlorothizide
or aldactone, see your doctor.
Since seniors are at high risk for dehydration, it is
important to “keep the tank full” at all times, to decrease
this risk. Drink plenty of water, unless your doctor has
instructed you not to do so because of liver or kidney
disease. Even if you are on a “water pill”, you need plenty
of water every day to keep the cells and the plasma healthy!
Enjoy the summer weather with a nice cold beverage (no
alcohol!!) and stay well! |
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