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Signs of Dehydration in the Elderly

Watch for early signs of dehydration to avoid serious complications.
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Written by
Petrina Craine, MD.
Assistant Clinical Professor of Emergency Medicine, Columbia University
Last updated January 21, 2021

Dehydration in the elderly questionnaire

What is dehydration?

Dehydration is caused by the body losing more water than it is getting.

The body is constantly losing fluid—through sweating, breathing, and urinating. Normally, you replenish these fluids when you eat and drink.

It is very common for the elderly—adults aged 65 and older—to get dehydrated.

Signs of dehydration in the elderly

Pro Tip

Sometimes patients tell me that they cannot “overdose” on water. That’s not true. Too much water can have negative effects on your body. Although rare, drinking too much water, often too quickly, can lead to a potentially fatal condition of low sodium levels called hyponatremia. —Dr. Petrina Craine

There are many signs and symptoms of dehydration in the elderly. Blood and urine tests can look for imbalances to help diagnose dehydration in the elderly.

The most common symptoms of mild dehydration are:

  • Headache
  • Nausea
  • Changes in urine (dark urine and decreased amounts)

Other symptoms of dehydration include:

Signs of severe dehydration include:

  • Confusion
  • Feeling disoriented
  • Trouble walking
  • Skin changes, for example, decreased sweating, sunken eyes, and skin tenting (skin that does not easily return to its normal position when delicately pinched)
  • Drop in blood pressure
  • Increased rate of breathing
  • Elevated heart rate
  • Fainting
  • Seizures

Dehydration can be dangerous in the elderly, partly because some symptoms typically used to diagnose it may be masked. For example, skin tenting may not be easily detected in elderly patients due to the frail, thin skin many elders develop. Also, dry mouth could be mistaken as a side effect of a daily medication.

These could lead to delays—sometimes fatal—in diagnosing dehydration early on in elder adults.

Why do the elderly get dehydrated more often?

Pro Tip

An important question to ask your doctor is, “Can we go over my or my loved one’s medications?” Especially in the elderly, dehydration can be caused by interactions with multiple medications combined with bodily changes in thirst and appetite and with medical problems such as kidney disease. —Dr. Craine

Dehydration affects people of all ages but adults aged 65 and over have a greater risk. Studies estimate that about 40% of elder adults are not hydrated enough, according to SAGE Open Nursing. These factors put elderly more at risk:

Less total body fluid

With age, the body loses more muscle and gains more fat. This affects your ability to maintain the normal total amount of body water (TBW). TBW is usually about 60% in men and 50% in women. After age 60, these numbers decrease to about 50% in men and 40% in women. Less TBW increases the risk of dehydration.

Decreased thirst

Your ability to detect and respond to thirst decreases with age. Even though the elderly need to drink plenty of fluids to replace fluid losses, they may not feel thirsty so they drink less.

More health problems

Elder adults are more likely to have underlying health problems that increase their risk of dehydration. 

  • Declining kidney function means less efficient processing of fluids.
  • Memory problems like dementia can cause elders to forget to drink.
  • Decreased ability to walk and move around (mobility) can prevent seniors from getting water.
  • Difficulty with swallowing and bladder and bowel control (incontinence) contributes to dehydration.
  • Medications can also cause dehydration. Medications for high blood pressure, for example, can have a diuretic effect, meaning that more fluid is lost during urination.

Complications from other illnesses

The elderly are more likely to become dehydrated when they get sick from other illnesses. For example, diarrhea and vomiting from a stomach virus, fever from the flu, urinary tract infections, or lung infections, and increased heat-related illnesses (like heat exhaustion and heat stroke) during hot and humid seasons can all lead to dehydration.

Treating dehydration in an elder adult?

Dr. Rx

Not everybody has to drink eight 8 oz glasses of water a day! Calculate how much a person needs with the following equation: Weight (in pounds) X ⅓ = fluid in ounces (basically one third of their weight in fluid ounces). For example, a 140-lb elderly woman needs about 46 ounces of water (5.5 8-oz glasses). —Dr. Craine

If you detect mild dehydration (e.g., nausea and headache symptoms), it can easily be treated by drinking fluids like water and sports drinks. The symptoms should improve quickly. It’s important to get an elder to drink fluids immediately. Not treating mild dehydration early on can lead to worsening and even deadly health complications such as organ shutdown.

If you think an elder adult has severe dehydration (e.g., signs of confusion, inability to eat or drink, sunken eyes, poor skin bounceback, elevated heart rate, low blood pressure, fainting, or seizures), they should go to the hospital. They’ll likely be given fluids through an intravenous (IV) line.

Prevention

The best defense against dehydration is to stop it from happening in the first place. Here’s how to help elder adults get enough fluids:

  • Aim for 6 to 8 cups of fluid a day. Because many factors, like activity level, medications, weather, and chronic illnesses, affect how much water an elder should drink, there is no set consensus on a recommended amount for older adults. Some research shows that drinking about 7 cups of fluids in 24 hours helps prevent dehydration.
  • Make sure to limit or avoid foods that have a diuretic effect on the body (causing you to urinate more). These include caffeine, alcohol, and extremely sweet drinks.
  • Regularly drink fluids like water and sports drinks throughout the day rather than drink a lot at one time.
  • Eat foods with high water content such as fruits, vegetables, and low-salt or salt-free soups.
  • Some older adults find it helpful to keep a daily log of their eating, drinking, and daily weight.
  • Address problems with mobility, memory, and incontinence by helping to time toilet breaks and keeping water close by.
  • Limit exposure to weather that can cause dehydration such as hot summers and dry winters.
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Assistant Clinical Professor of Emergency Medicine, Columbia University
Dr. Petrina Craine is an emergency medicine physician who hails from Memphis, TN. After graduating as valedictorian of her high school, she moved to Durham, NC to pursue a degree in Biology and a certificate in Global Health. After college, she returned to her birthplace to attend the University of Tennessee Health Science Center College of Medicine. She successfully completed her medical degree a...
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