Why do elderly people suffer more easily from dehydration? Causes of dehydration and tips to improve fluid intake!

Why do elderly people suffer more easily from dehydration?

Normally, our summers tend to alternate between cooler and warmer days with plenty of rain, but at the moment we experience a prolonged period of unusually warm and dry weather.This is probably why it is not so common to warn against dehydration among elderly adults on hot summer days, which is a grave mistake. 

While even healthy younger adults have a hard time staying properly hydrated in the heat, elderly citizens have an especially hard time because they don't even drink enough in cooler weather.

It’s important to prevent dehydration because it’s a common cause of hospitalization in people over 65 and can even cause death.
Dehydration can also cause other major health problems like kidney stones, blood clot complications, passing out, rapid but weak pulse, and lowered blood pressure. Being properly hydrated is also very important for certain medications to work.

Because water has numerous functions in the human body, it is one of the most important nutrients and is essential in every life stage. However, with aging, the body’s mechanisms of water balance are disturbed, increasing the risk of dehydration among the elderly.
There are high rates of dehydration in the elderly population and dehydration is one of the ten most frequent diagnoses reported for hospitalisations of persons over 65 in the United States.

The elderly are at risk of dehydration

Dehydration is typically defined as depletion in total body water content due to fluid losses, diminished fluid intake, or a combination of both. Depending on the ratio between sodium and water losses, dehydration can be classified as
- isotonic with equal loss in sodium and water e.g. in diarrhea
- hypertonic with excess loss of water e.g. as a result of a fever
- hypotonic with excess loss of sodium , e.g. upon overuse of diuretic medicine

There are several reasons why elderly in particular have a higher risk of dehydration

1 decreased water stores

As we age, we lose a steady amount of muscle mass, which is the body's main storage of fluids. As a result, the total amount of water that is stored in the body also decreases with age.

2 thirst sensation

The elderly often experience reduced thirst sensation which leads to decreased fluid consumption.
The exact reason is not well known and probably caused by various changes in how the human body measures thirst on hormonal and neurotransmitter level.
The most important hormone involved in thirst management is the Atrial Natriuretic Peptide, a well-known thirst inhibitor of which plasma levels are higher among elderly people. Dopamine is a neurotransmitter, which is also involved with the thirst sensation.

3 kidney function

As a consequence of aging, renal water conservation is impaired. Aged kidneys are less able to concentrate urine, and thereby to retain water during water deprivation. Age-related lower responsiveness of the kidney to the Anti-Diuretic Hormone (ADH), is thought to play an important role in this loss of renal function.
In addition, aging kidneys have a lower ability to adequately regulate sodium excretion.
Thus, in older individuals, aged-related physiological changes occur and these make the body less able to maintain water homeostasis.

4 additional factors

In addition to age-related changes in the body, many other factors put the elderly at risk of dehydration.
Aging is associated with limitations such as reduced swallowing capacity, reduced mobility, or communication problems, which can lead to insufficient fluid intake.
Disease-related factors, such as fever, diabetes, or incontinence can increase water losses.
Dehydration may also be caused by environmental factors (warm temperature, inadequate knowledge or the lack of time of care workers in institutions) contributing to inadequate fluid intake or because of medication such as laxatives, diuretics or ACE-inhibitors.

Dehydration: an actual concern for the elderly population

Dehydration is a major problem among elderly people both when they are still at home or at institutions and can run up as high as 90% among residents of nursing homes.

As daily water needs strongly depend on various factors like fluid losses and dietary composition, the estimation of water requirement is highly variable and quite complex. This is particularly true for the elderly for whom health conditions such as congestive heart failure and kidney diseases or medication use (diuretics or laxatives) highly influence fluid needs.

Only a few countries have established national recommendations for fluid intakes and existing recommendations vary between countries.
In the USA, total fluid intake (water from both beverages and foods) is 3.7L for elderly men and 2.5L for elderly women.
In Europe, EFSA (European Food Safety Authority) recommends 2.5L for elderly men and 2L for elderly women.

How much water do elderly people drink?

Despite the general consensus that an appropriate level of fluid intake is essential for health, not all that much is known how much fluid elderly people actually consume.
From a limited amount of studies it is known that total fluid intake steadily decreases with age within the elderly population and that this decrease is mainly driven by a decrease in water intake from beverages, including drinking water.

Comparisons between observed fluid intakes indicate that a substantial proportion of the elderly population may be at risk for insufficient fluid intake and thereby of dehydration, especially among seniors over age 85.
In a German study among independently living elderly people, found that one-third of them did not meet the recommended total fluid intake in which especially fluid intake from beverages was lacking.
In an American study, up to two-thirds (63%) of the young elderly (65-74 y) and the vast majority (81%) of the oldest elderly (85+ y) were shown to have have inadequate total fluid intake compared to the recommendations.

Health consequences of dehydration

Staying well hydrated is important for proper function of the whole human body. Being dehydrated has many negative health consequences, especially in the older person, for whom dehydration is frequent and can be fatal if undiagnosed.

In a study of American seniors hospitalised with dehydration, the mortality rate in the following year was nearly 50%.
There is increasing evidence that dehydration, even its mild form, plays a role in the development of various ailments.
The most common consequence of dehydration is constipation, followed by impaired cognitive function, higher risk of falling, higher body temperature, and problems in controlling blood sugar level as well as maintaining normal blood pressure.
Other problems that can occur with dehydration are urinary tract infections and development of kidney stones.

It is estimated that dehydration is 1 of the 5 most expensive health conditions, with a treatment cost reaching approximately $1,000 per dehydration episode in nursing homes up to $7,500 when hospitalised.

Diagnosing dehydration

There is no universally accepted method to evaluate dehydration in the elderly since classical signs and symptoms of dehydration, especially those resulting from mild dehydration are often more difficult to recognise in the elderly than in adults or children, including
- dryness of the mouth
- muscle weaknesses
- poor skin elasticity
Moreover, some symptoms may even be absent, such as increased thirst.

Therefore it is recommended to look at several different indicators for dehydration, requiring
physical examination for
- dry tongue and mouth
- lacking muscle strength
- general confusion
- speaking difficulties
- sunken eyes
- low blood pressure
- low heart rate
- rapid weight loss of more than 1kg a day

and if necessary, also the use of laboratory tests for
- increased serum creatinine levels
- increased serum urea levels
- abnormal serum sodium levels
- abnormal urine production

Dehydration treatment strategies

Depending on the severity and type of dehydration, 4 therapeutic strategies exist: oral, enteral, subcutaneous or intravenous administration.
The choice of the rehydration methods depends on complications that influence urgency of rehydration and the availability of facilities.

Whenever possible, oral fluids are preferred as long as symptoms are not truly severe and fluids can be restored gradually over time.
When oral fluid intake is insufficient, fluid administration via a nasal feeding tube is advisable. It allows an early and rapid rehydration, without risk of overload.
Intravenous therapy is effective when the dehydration is severe and when the clinical state of the patient demands an acute intervention.
In addition to its potential risk and its expensive cost, a major drawback to this option is that it requires qualified staff, and generally, hospitalisation.
Despite these disadvantages and recommendations for oral therapies, intravenous strategies are favoured by caregivers in practice.
An interesting alternative with a low risk of complication is the subcutaneous infusion of fluids.
Subcutaneous infusion can be effectively used in elderly people living in nursing homes, so that hospital admission may be avoided.

Because intervention procedures are so costly, they mostly only happen when patients are already severely dehydrated, a situation that is best avoided.
In addition: from experts we hear that nowadays there is enough trained staff to do this procedure and in addition, subcutaneous hydration is experienced to be painful by dehydrated patients.

Dehydration prevention strategies

Prevention of dehydration in the elderly is primarily based on ensuring adequate fluid intake.
Raising awareness among the elderly, their famililies and caregivers of the importance of dehydration and its risk factors is fundamental for dehydration prevention.

Tips to improve fluid consumption are:
- offer fluids throughout the day and make them easily accessible at the bedside or attached to their wheelchair
- use logical timing for drinking e.g. along with medication intake, after urination and with meals or when taking a break during activities, so that small amounts add up to the recommended daily fluid intake

For the elderly that experience urinary incontinence, measurements should be taken so that patients will be less likely to avoid fluid intake.
Family members and caretakers should carefully monitor fluid status of the elderly in order to make sure they drink the required amount of 1.5 litre of liquids. Keep a pitcher in the refrigerator with the day’s allotment of water. You will know how much more is needed to get enough and see if your senior is drinking enough.

Fortunately dehydration prevention can be as simple as frequent verbal reminders to drink up as well as providing more drinking cups and bottles.

What type of fluid should be recommended?

Water is obviously the first fluid that comes to mind and should constitute the bulk of daily intake. Adding ice cubes or switching out regular water with soda water can already do the trick in order to make people reach for water more often. Make sure the ice cubes are made and stored with proper care of hygiene. 

Milk, fruit juices and non-salty soups are nutritious and can be useful in providing variety, especially to those that don't enjoy drinking water.
(Iced) coffee and tea can have a diuretic effect and should therefore be consumed in reasonable amounts. It stands to reason that alcoholic beverages are not recommended.
Another solution is to offer fruits and vegetables with a high water content such as water melon, strawberries and cucumbers.
Home-made popsicles from fruit juice, smoothies, milkshakes, are great summer treats and good ways to increase fluid intake.

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