Dehydration affects 20% to 30% of older adults and is usually caused by insufficient water intake. It may also be caused by excess water loss through diarrhea, vomiting, sweating, high fever, or side effects from medication.
Dehydration occurs when a person loses more water than they take in. Water serves many purposes in the body, including producing energy, optimizing brain function, regulating body temperature, ridding the body of toxins, and lubricating joints.
This article reviews dehydration in older adults, including symptoms and signs to watch out for. Rehydration strategies and insight into why older adults are more vulnerable to dehydration will also be provided.
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Symptoms to Look for
Symptoms and signs of dehydration in older adults include the following:.
Bathroom Habits
Constipation or straining during a bowel movement is a common sign of dehydration, as water softens stool, making it easier to pass.
When dehydrated, a person’s urine turns dark yellow, indicating it is more concentrated. Urinating less frequently or noticing a smaller urine volume when using the bathroom are also common. However, the presence or absence of these urine symptoms is not reliable for diagnosing dehydration in older adults.
Cognitive, Mood, and Behavior Changes
Cognitive performance is affected in individuals with more than 2% body water loss. Areas of cognition most affected by dehydration include:
- Attention span
- Executive function, including the ability to focus and follow directions
- Motor coordination, such as with brushing teeth or buttoning a shirt
- Short-term memory skills
Dehydration can also affect mood.
In one small study, adults who were habitually high-volume water drinkers (2 or more liters of water per day) reported diminished feelings of contentedness, calmness, positive emotions, and vigor after decreasing their water intake.
In another study of older adults, malnutrition along with dehydration due to low intake of fluid was associated with the following mood changes:
- Depression
- Irritability
- Apathy (feeling of indifference)
- Decreased ambition and self-discipline
Muscle Effects
Dehydration in older adults is associated with muscle catabolism—when the body favors muscle breakdown as a source of energy, as opposed to carbohydrates or fat.
Dehydration can also cause electrolyte imbalances (electrolytes are charged minerals in the body, including sodium, potassium, and calcium).
The combination of muscle catabolism and electrolyte imbalance can cause muscle weakness, aches, cramps, twitches, and spasms.
Other Symptoms
Other potential symptoms of dehydration are:
- Dry lips/tongue due to decreased saliva production
- Fatigue from reduced water content within the body’s tissues
- Weight loss from loss of “water weight”
- Headache, believed to be caused by the activation of pain receptors within the tissues lining the brain (meninges)
Severe
In severe cases of dehydration, hypernatremia or hypovolemic shock can develop.
Hypernatremia is characterized by elevated sodium levels in the bloodstream. In older adults, it’s often caused by severe or prolonged poor water intake. Symptoms can include weakness and irritability, progressing to muscle twitching, seizures, coma, and potentially death.
With hypovolemic shocka person’s blood pressure becomes so low that oxygen delivery to vital organs is impaired.
Symptoms of this potentially life-threatening condition include:
- Poor skin turgor (elasticity)
- Cool skin
- Rapid heart and breathing rate
- Lack of urination
- Confusion
- Light-headedness when standing up (orthostatic hypotension) and fainting
Comorbidities in Older Adults and Effect on Dehydration
Older adults are vulnerable to dehydration for various age and health-related reasons.
Age
As adults age, they are at a higher risk for dehydration due to these phenomena:
- Decreased sensitivity to thirst
- 10% reduction in total body water content due to reduced muscle mass
- Reduced ability of the kidneys to hold onto water
- Diminished ability to deal with heat stress
- Taking medications associated with water loss—for example, diuretics (“water pills”) or laxatives
Physical Health
Older adults are also more likely to have health conditions, such as diabetes or an enlarged prostate, that may cause them to wake up at night to urinate (nocturia). To avoid disrupting their sleep, they may purposefully drink less.
Those with urinary incontinence are also prone to dehydration. They might restrict themselves from drinking to avoid having an accident.
Mobility issues or severe joint diseases, such as osteoarthritis (progressive disease that causes a loss of protective cartilage around joints), can also make it difficult to access water independently.
Dementia
Dementia comprises a series of conditions (e.g., Alzheimer’s dementia and vascular dementia) associated with brain changes that cause cognitive decline. Age is the strongest risk factor for dementia.
With dementia, a person may forget to drink or have difficulties communicating their thirst to caregivers. Psychological effects of dementia, like depression, apathy, or agitation, can limit participation or interest in mealtimes or activities where drinks are served.
Dementia can also reduce a person’s sense of smell and taste and cause motor (movement-related) problems like difficulty swallowing. These physical changes can impair adequate hydration.
Major Risk Factor for Dehydration
Individuals with dementia are 10 times more likely to be admitted to the hospital for dehydration compared to adults of the same age without dementia.
Chronic Dehydration in Older Adults
Dehydration is classified as either acute or chronic:
- Acute dehydration often results from transient factors or scenarios such as water loss from excessive sweating or infection (e.g., high fever, vomiting, excessive sweating, or diarrhea.)
- Chronic dehydration occurs when there is inadequate water intake to compensate for fluid loss over a prolonged period. Compared with acute dehydration, symptoms and signs can be more subtle.
Chronic dehydration in older adults is linked to several adverse health problems, including falls, constipation, urinary tract infections (UTIs), worsened memory performance, and an increased risk of being hospitalized.
Moreover, if an older adult (65 years or older) is hospitalized for another reason, dehydration can lead to a poorer prognosis (outcome) for the condition being treated.
Treatment
Dehydration is treated by restoring the water content that has been lost. Older adults with mild dehydration who can drink independently can usually rehydrate at home.
Severe dehydration requires hospitalization with intravenous (IV, through the vein) fluids and, sometimes, other measures, depending on the underlying cause.
Talk with a healthcare provider if you are uncertain about the severity of your (or your loved one’s) dehydration, or if you have underlying health conditions, like kidney disease or heart failure, that may require medical monitoring of fluid intake.
At Home
Rehydration at home requires taking small but frequent sips of water containing electrolytes such as sodium and potassium.
Oral rehydration solutions (ORS) are available at local grocery stores or pharmacies. These solutions differ from sports drinks (Gatorade) in that they contain the correct amount of electrolytes needed for rehydration.
Keep in mind that ORS is contraindicated in those who have severe dehydration, are unable to drink liquid, have prolonged/severe vomiting, or have an intestinal blockage or ileus (slowed or stopped intestinal motility).
While rehydrating, it’s crucial to be seen at a hospital emergency department if symptoms of dehydration continue despite drinking fluids.
Likewise, contact a healthcare provider or seek medical care if the cause of dehydration (e.g., vomiting or diarrhea) persists. Medicine to ease the vomiting or diarrhea may be needed.
Seek Emergency Medical Attention
Call 911 or go to your nearest emergency room if you have:
- Confusion or drowsiness
- Severe fatigue or weakness
- Light-headedness and/or fainting
- Inability to drink fluids due to problems swallowing or vomiting
- No urination
At a Medical Facility
Oral rehydration solutions and intravenous (IV) fluids can be administered at a medical facility. They are generally administered at a rate based on body weight.
During rehydration, a person’s hydration status is closely monitored by evaluating various factors, such as urine color and concentration, heart rate, blood pressure, and changes in body weight.
Preventing Dehydration in Older Adults
The recommended water intake for females is 1.6 liters per day and 2 liters daily for males.
However, this recommendation is not a hard-and-fast rule. A person’s fluid needs may be lower or higher based on underlying medical conditions and activity level.
Tips for preventing dehydration in older adults include:
- Drink small, frequent sips of water, tea, or fruit juice (dilute with water) throughout the day.
- Eat hydrating foods like cucumber, celery, iceberg lettuce, strawberries, and watermelon.
- Consume meals with others to encourage adequate nutrition and hydration.
- Drink more fluids if engaging in physical activities or if in the heat.
Tips for preventing dehydration in older adults living in long-term care facilities include:
- Schedule routine and frequent “drink rounds” throughout the day.
- Encourage increased fluid intake when taking medications.
- Ensure safe and easy access to bathrooms and availability of support.
- Consider individual preferences of drink and presentation—for example, flavored sparkling water in a favorite mug.
Summary
Dehydration occurs when a person has insufficient water due to poor intake or excess loss (e.g., vomiting or diarrhea).
Older adults are prone to dehydration for many reasons, including a diminished sensation of thirst, medication side effects, and health conditions like diabetes, enlarged prostate, or arthritis.
Dementia is another major dehydration risk factor in older adults due to its cognitive (e.g., forgetting to drink), psychological (e.g., loss of interest in drinking), and physical (e.g., problems swallowing) effects.
Symptoms of dehydration in older adults include constipation, dark-colored urine, difficulty paying attention, irritability, muscle cramps, dry mouth, fatigue, and weight loss. When severe, dehydration can cause symptoms of shock, including confusion, fainting, poor skin elasticity, and a fast heart and breathing rate.
Mild dehydration can usually be treated at home with oral rehydration solutions. For severe dehydration or in scenarios where a person cannot drink liquids or has health conditions that require close monitoring (e.g., protracted vomiting or kidney/heart failure), hospitalization with IV fluids is necessary.
