Last Updated: April 4, 2013
Watching for signs of illness in a loved one can be challenging.
Some illnesses show up quite clearly, while others have a more
subtle effect on daily living. Dehydration, depending on the
severity, sometimes creates only small telltale signs while having
a big effect on the body, especially in the elderly.
Dehydration occurs when a person loses more water than they take
in. It takes an adequate amount of fluid for the body to function
properly; for example, to regulate body temperature through
sweating, maintain blood pressure, and eliminate bodily waste. If
severe enough, dehydration can lead to confusion, weakness,
urinary tract infections,
in bed-ridden patients, or even death. In general, a human can
survive for only about four days without any fluids.
Elderly dehydration is especially common for a number of
reasons: some medications, such as for high blood pressure or
anti-depressants, are diuretic; some medications may cause patients
to sweat more; a person's sense of thirst becomes less acute as
they age; frail seniors have a harder time getting up to get a
drink when they're thirsty, or they rely on caregivers who can't
sense that they need fluids; and as we age our bodies lose kidney
function and are less able to conserve fluid (this is progressive
from around the age of 50, but becomes more acute and noticeable
over the age of 70). Illness, especially one that causes vomiting
and/or diarrhea, also can cause elderly dehydration.
"Everybody has a normal state of body water that relates to
their weight. Anything below that (normal state) is dehydration;
everything above it is hyperhydration," Dr. Larry Kenney, professor
of physiology and kinesiology at Penn State University,
That normal level of hydration varies widely from person to
person. Contrary to the mantra that everyone should drink eight
glasses of water every day, Kenney says there is nothing scientific
to back that up. "People misinterpreted that to be, it had to be
liquid and it had to be water," he says.
A person's diet can greatly affect hydration levels: fruits
(especially watermelon), vegetables, and soups are mostly
water-based. "Day in, day out, a lot of people get their water from
foods, as well as behavioral attitudes towards food," Kenney
explains. "For instance, when we walk by a water fountain, we tend
to take a drink, and we tend to drink when we eat."
Kenney also takes issue with the idea of not drinking
caffeinated beverages because they're dehydrating. He says the
amount of caffeine in a cup of coffee or tea is relatively small,
and it's made of mostly water anyway, so it will hydrate you to
some degree. The same holds true for beer, he says, but there is a
point at which the diuretic effect of caffeine and alcohol kicks
in, so moderation is always the key.
In general, larger people need to drink more water, as do
athletes and those who perspire heavily, but that may mean more or
less than eight glasses a day. "There is no one-size-fits-all
remedy," he says.
Instead, he recommends monitoring body weight to keep track of
hydration levels. To monitor body weight, one should be weighed
every morning. If they've lost two pounds or more from the day
before, and especially if they feel thirsty or have a headache,
they're probably dehydrated.
Mild dehydration is defined as losing 2 percent of your body
weight. Severe dehydration occurs with 4 percent or greater body
weight loss. Even mild dehydration can affect a person's health,
especially if he already has cardiac or renal problems. "We have
measured in the lab cognitive impairment," he says. "With severe
dehydration, it puts a greater strain on the heart. Think of a pump
trying to pump with less fluid. That would be one of the primary
Kenney says an active 65-year-old who exercises probably doesn't
need to weigh herself every day, but a 75-year-old in a nursing
home who has had issues with dehydration in the past or has had
cardiac issues, should be weighed every day.
But, don't rely on scales that also claim to measure hydration
levels and body mass index. "Their accuracy is very poor; we can't
use them even for research purposes," Kenney says.
Complicating matters is that signs of dehydration in younger
people don't always show up in the elderly. For example, if a young
person was extremely dehydrated, his skin may be wrinkled or
sagging. But, that certainly wouldn't be noticed in most cases of
Perhaps because of that delay in diagnosis, elderly dehydration
is a frequent cause of hospitalization (one of the ten most
frequent admitting diagnoses for
Medicare hospitalizations, according to the Health Care
Financing Administration), and it can be life-threatening if severe
Other signs of dehydration to look for: confusion, problems with
walking or falling, dizziness or headaches, dry or sticky mouth and
tongue, sunken eyes, inability to sweat or produce tears, rapid
heart rate, low blood pressure or blood pressure drops when
changing from lying to standing, and constipation or decrease in
urine output. Also check for a decrease in skin turgor-pull up the
skin on the back of the hand for a few seconds; if it does not
return to normal within a few seconds, the person is
To help make sure your loved one doesn't suffer from elderly
dehydration, make sure he or she consumes an adequate amount of
fluids during the day; eats healthy, water-content foods such as
fruit, vegetables and soups; checks that urine color is light and
output adequate (dark urine or infrequency of urination is a
classic sign of dehydration).
Seniors also need to be educated to drink even when they're not
thirsty. Keeping a water bottle next to the bed or their favorite
chair could help, especially if they have mobility issues.
If your loved one is in a nursing home or
other care facility, make sure that the staff has a hydration
program in place, including assisting residents with drinking,
offering a variety of beverages (remember, taste buds change with
age, so a beverage they used to enjoy may no longer taste right),
and providing drinks not only at mealtimes but in between meals.
Also make sure that they monitor residents'
weight and assess them if their physical condition or mental
state changes. If dehydration is an issue and your loved one takes
laxatives or diuretics, speak to his or her doctor about changing
As with most illnesses, prevention is the key. Making sure your
loved one stays hydrated now is much easier than treating him or
her for dehydration later.