Most Common Dehydration Symptoms in Elderly People

author avatar Dr. Eric Berg 01/02/2024

Many older adults have a reduced sense of thirst, which can lead to inadequate fluid intake and dehydration. Even mild dehydration can impair crucial physiological functions, leaving older people at risk of various health issues.      

Let’s look at common dehydration symptoms in elderly people and discover how using an electrolyte powder can be the key to staying hydrated. 

Unhealthy mature woman

What is dehydration?

Dehydration occurs when fluid loss exceeds fluid intake, leading to a drop in total body fluid volume.  

Water is an essential component of all cells, tissues, and organs, and insufficient fluid balance in the body can impair crucial physiological functions, including nutrient transport, detoxification, waste excretion, temperature control, brain function, and digestion.     

Dehydration is classified into mild, moderate, and severe cases based on the extent of the body's fluid deficit. 

While mild dehydration isn’t a medical emergency and can typically be managed by drinking fluids, severe dehydration can lead to serious complications and may potentially be life-threatening.   

Watch the video below to discover why drinking water isn’t the best way to stay hydrated.  

Common dehydration symptoms in elderly people

Thirst is typically the first sign of dehydration and a critical signal to prompt the need to replace lost fluids. 

However, as we age, changes in sensory perception can lead to a diminished thirst sensation, leaving older adults at risk of inadequate fluid intake and dehydration. 

Although thirst may not be a prominent dehydration symptom in older people, many other signs can indicate dehydration in the elderly. 

Here are common symptoms of dehydration in older people:

  • Dry mouth

  • Decreased need to urinate

  • Dark colored urine

  • Constipation

  • Low blood pressure

  • Recurring urinary tract infections

  • Irritability

  • Poor memory 

  • Muscle weakness or cramps

  • Dizziness

  • Dry skin 

Because water is vital for almost all biochemical processes, dehydration can worsen various health issues and may be especially detrimental to elderly patients with urinary and kidney problems, diabetes, and cardiovascular issues.  

Electrolyte test sample

Dehydration causes and risk factors

While a lack of adequate fluid intake is a leading cause of developing dehydration, there are several other factors that can contribute to fluid loss.

Here are common causes of dehydration in older people. 

1. Medical conditions

Certain medical conditions, such as diabetes, kidney disease, chronic diarrhea, and adrenal gland disorders, can lead to excessive fluid loss and an increased risk of dehydration.

2. Electrolyte imbalance

The body’s fluid balance is tightly controlled by electrolytes, including sodium, chloride, and potassium. 

These essential electrolytes facilitate the movement of water into and out of cells, and electrolyte imbalances can result in dehydration despite consuming plenty of fluids.

While most people obtain enough sodium and chloride from table salt, potassium deficiency is widespread as many people consume only a fraction of the recommended daily allowance (RDA) of 4,700 milligrams of potassium. 

Research published in Clinical Chemistry found that most adults aged 75 years and older don’t consume adequate amounts of potassium-rich foods, leaving them at risk of deficiency. 

Low potassium levels, especially in combination with a high-sodium diet, can imbalance the potassium-to-sodium ratio in the body, which is crucial to maintaining optimal fluid balance and preventing dehydration. 

3. Medication use

According to a report published by the National Institute of Aging (NIA), ”People aged 65 and older tend to take more medicines than those in any other age group.” 

Certain medications trigger fluid or electrolyte loss, and individuals who take blood pressure medications, diuretics, laxatives, or antidepressant drugs are at increased risk of dehydration.

4. Heat exposure

Age-related changes in central nervous system functions can impact the body’s ability to regulate body temperature, which can lead to excessive sweating and fluid loss, especially in hot and humid climates.

Senior man holding a glass of water

How to rehydrate safely

Most cases of mild to moderate dehydration can be managed without the need for medical attention by drinking plenty of water and replenishing electrolytes. 

Isotonic drinks may seem like a convenient source of electrolytes. Unfortunately, many sports drinks can lead to weight gain and dehydration due to their high sugar and sodium content.  

“While endurance athletes may benefit from replacing lost sodium, most people already consume enough sodium through dietary sources, which can exacerbate dehydration,” explains Dr. Berg.  

A high-potassium electrolyte powder that’s low in sodium is an excellent choice to restore electrolyte balance and rehydrate the body. 

Look for an electrolyte powder formulated with around 1,000 milligrams of potassium and 40 milligrams of sodium.

A study published in Nutrients confirms that maintaining a low sodium-to-potassium ratio in the body promotes optimal cellular fluid concentrations and lowers the risk of high blood pressure. 

Electrolyte powder

Elderly dehydration prevention

Older adults are more susceptible to dehydration, and promoting balanced fluid levels is crucial for maintaining overall health and well-being.

It’s important to encourage older adults to drink by keeping water within easy reach and suggesting set times for fluid intake, such as the first thing in the morning, before and after each meal, and when taking medication. 

A high-potassium electrolyte powder can help counteract electrolyte loss and prevent dehydration. Electrolyte replacement can be especially beneficial for older individuals with low potassium intake, those taking prescription medications, and elderly patients with underlying health conditions. 

Consuming hydrating foods such as soups, stews, and vegetables, including cucumber, radishes, celery, tomatoes, bell peppers, cabbage, and spinach, can also help maintain hydration levels and lower the risk of dehydration.

Senior man with a nurse

When to see a doctor

Cases of severe dehydration in elderly individuals can lead to kidney failure, dangerously low blood pressure, seizures, and even coma.   

If you notice symptoms such as dark urine, sunken eyes, a dry mouth, dizziness, mental confusion, a rapid heartbeat, or fatigue, it’s crucial to seek medical attention immediately.

The treatment of severe dehydration in older adults may require hospitalization and the supervised administration of intravenous fluids and electrolyte replacement therapy to gradually increase body fluid volume.    

Senior couple drinking water

Key takeaways

Thirst sensations diminish as we age, and it’s essential to be aware of common dehydration symptoms in elderly people, such as dry mouth, dark-colored urine, low blood pressure, irritability, and poor cognitive functions. 

Drinking plenty of water, consuming hydrating foods, and replenishing electrolytes with a potassium-rich electrolyte powder helps maintain optimal fluid balance and lowers the risk of dehydration in older adults.  


1. How can you tell if an elderly person is dehydrated?

Early warning signs of dehydration in an elderly person may include a dry mouth, sunken eyes, darker urine, a decreased need to urinate, and confusion.

2. What happens when an older person gets dehydrated?

Dehydration in an older person can impair critical physiological functions, which can result in electrolyte imbalance, poor muscle and kidney function, low blood pressure, and cognitive problems. 

Chronic dehydration can exacerbate existing health problems, interfere with the effectiveness of prescription medications, and increase the risk of infections, poor mental health, and heat-related illness.    

3. What is the fastest way to hydrate an elderly person?

The most effective way to hydrate an elderly person involves drinking plenty of water and restoring electrolytes with an electrolyte powder that contains around 1,000 milligrams of potassium and 40 milligrams of sodium.

4. What happens when seniors don't drink enough water?

Insufficient water intake in seniors can result in dehydration, which occurs when fluid loss exceeds fluid intake. 

Older adults are at greater risk of severe dehydration if they don’t drink enough water as they tend to have less total body fluid volume than younger age groups. 

5. Can dehydration make you sick?

Yes, dehydration can make you sick as it can worsen existing health conditions and increase the risk of urinary tract infections, kidney problems, blood pressure issues, poor muscle functions, and cognitive decline. 


6. How long does it take for an elderly person to recover from dehydration?

How long it takes for an older person to rehydrate depends on the severity of the dehydration and the individual's overall health status. 

While mild cases of dehydration can typically be resolved within a day, more severe fluid loss may require considerably longer periods of consistent fluid intake and electrolyte replacement.    

7. What is the most common cause of dehydration in older adults?

Older adults have a diminished sense of thirst, causing inadequate fluid intake, which is the leading cause of dehydration in older adults. 

8. What is the best drink for dehydration in seniors?

The best drink for dehydration in seniors is electrolyte water made with an electrolyte powder that contains about 1,000 milligrams of potassium and 40 milligrams of sodium. 

9. How can you tell if someone is dangerously dehydrated?

Symptoms such as sunken eyes, dark urine, dry mucous membranes, reduced need to urinate, dizziness, and confusion are signs of significant fluid loss and indicate that an individual requires medical attention to treat dehydration. 

10. When should an elderly person go to the hospital for dehydration?

An elderly person should go to the hospital for dehydration if they experience symptoms such as dry mouth, very dark urine, confusion, or dizziness.  

In addition, it’s crucial to seek medical care if rehydration attempts at home are ineffective, as this may indicate a more serious underlying medical issue. 





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