Updated

How Much Water To Drink A Day For Older Adults

Written by 
Molly Burford
Reviewed by 
Emanuel Singleton, NP
Article at a glance
  • Adequate hydration is imperative for healthy living and keeps the body functioning properly.

  • Fluid needs will vary on an individual basis and are dependent on many factors including body weight, physical activity, etc.

  • Seniors are at an increased risk for dehydration.

  • While other beverages can be good sources of hydration, plain water is always the best choice when possible.

older man drinking water bottle in gym

Staying hydrated is important for overall health because water is involved in all bodily functions and helps the body to function properly. But how much water should you drink daily? 

This resource will explain the benefits of hydration, how to stay adequately hydrated, and how to avoid dehydration.

The Health Benefits of Drinking Water

Water is essential to all bodily functions and good health. Some of the health benefits of drinking water and examples of how it regulates the body include:

  • Carries nutrients and oxygen to cells

  • Flushes out bacteria 

  • Helps digestion

  • Prevents constipation

  • Regulates blood pressure

  • Cushions joints

  • Protects organs and tissues

  • Regulates body temperature

  • Maintains electrolyte (sodium levels) balance

  • Can help one to lose weight

person pouring water into glass from metal pitcher

How To Calculate How Much Water To Drink A Day

While many people have probably heard of the recommendation to drink eight glasses of water daily, it isn’t always that cut and dry because daily fluid intake needs will vary from person to person. For example, marathon runners will have different water intake needs than more sedentary individuals.

How much water is enough to stay hydrated is based on a variety of factors including: 

  • Environment: Those who live in a temperate climate will have different fluid needs than those who live in the mountains or incredibly hot areas.

  • Activity levels: Those who are more physically active will need to drink more water than those who are sedentary. 

  • Diet: Those who eat high-sodium, sugar, or spicy diets will need to drink more fluids than others.

  • Health: People with certain health conditions such as diabetes will need to consume more fluids as well as those on particular medications. 

  • Weather and/​or season: Fluid needs will change with the seasons and depending on the weather. For example, someone will need to increase their fluids on a hot day in the summer because they will lose water through sweat.

Water Intake Formula 

One formula to help someone know how much water they need is to drink half an ounce of water per every pound of body weight. For example, someone who weighs 160 pounds would need to drink 80 ounces of water daily. 

Note: Learn more about fluid intake calculations at this resource.

Signs Of Proper Hydration

In general, the best way to know someone is hydrated is through the color of their urine. Light yellow is the ideal shade. If the urine is dark yellow, dehydration is likely and they will need to drink more water.

Older man stretching outside in urban area

Dehydration And Older Adults

20 to 30% of older adults are affected by dehydration. This occurs most likely due to a lack of fluid intake but can be the result of excess water loss as well. Dehydration is such a prevalent issue with seniors that it is also a common cause of hospitalization for this age group.

Signs Of Dehydration

According to Harvard Medical School, the signs of dehydration include: 

  • Weakness

  • Low blood pressure

  • Dizziness

  • Confusion

  • Dark-colored urine

When Is Dehydration An Emergency? 

Some cases of dehydration may call for emergency care and hospitalization. Signs of dehydration that indicate a healthcare provider is needed or that 911 should be called include:

  • Weakness

  • Diarrhea

  • Dizziness

  • Fainting

  • Confusion

  • Blood in vomit or stool 

Dehydration Risks

Being dehydrated can lead to many risks such as:

  • Kidney stone development

  • Increased likelihood of hospitalization

  • Decreased bowel movements and constipation

  • Higher risk of developing bladder infections

  • Lower energy levels and overall fatigue

water pitcher with lemons on countertop

How To Prevent Dehydration

Because dehydration has a number of negative effects, especially for older adults, it is important to make sure one is consuming enough water throughout the day. In addition to drinking more water, some other tips for preventing dehydration include:

Adjusting Diet

Cutting back on salty foods, avoiding or reducing alcohol intake, and drinking caffeine in moderation can help ensure someone is retaining enough fluid.

Eating Water-Dense Foods

Adding more water-rich foods to one’s diet can also increase water balance in the body. Some examples of such foods include fruits and vegetables.

Consume Additional Fluids 

Milk, sports drinks, soup broths, juices, and even caffeinated drinks like tea can help keep someone stay hydrated. When it comes to caffeinated beverages, however, remember moderation is key.

Consistently Drink Water

Drinking enough water throughout the day is much easier than trying to drink a ton of water in one sitting, therefore it’s crucial to actively drink water daily to ensure you remain hydrated.

Try Making Flavored Water

Mixing fruit, electrolyte powders, or flavored drops with plain water can make drinking it less cumbersome and boring.

Prevent Fluid Loss

Preventing fluid loss is imperative to preventing dehydration, especially for older adults. Ways to prevent fluid loss include drinking more water on a hot day, replenishing fluids following exercise, etc.

Is There Such Thing As Drinking Too Much Water?

Yes, it is possible to drink too much water, especially with certain health conditions such as kidney, liver, and heart issues. Certain medications can also cause water retention including non-steroidal anti-inflammatory drugs (NSAIDs), opiate pain medications, and some antidepressants. 


Note: Those who have one of those health conditions or take any of the aforementioned medications should discuss their fluid intake requirements with their healthcare provider to ensure they are not drinking too much water.

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