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Experts say hydration is particularly important for older adults. PhotoAlto/Frederic Cirou/Getty Images
  • Researchers say staying hydration by drinking water throughout the day can improve healthy aging and reduce the risk of chronic diseases.
  • They say hydration is effective mainly because it helps lower serum sodium levels.
  • They say hydration is particularly important for older adults.

Staying hydrated could lead to healthy aging as well as reduce your risk of developing chronic disease and help you to live longer, according to a new study published in eBioMedicine.

Researchers looked at health data from 11,255 adults over a 30-year span via the Atherosclerosis Risk in Communities (ARIC) study.

They based their findings on information shared by the participants during five medical visits. The first two visits were when participants were in their 50s. The last was between the ages of 70 and 90.

Specifically, the scientists looked at serum sodium levels, which rise when fluid levels in the body go down. The serum sodium levels indicate the amount of sodium in your blood, according to the National Library of Medicine.

Sodium is an electrolyte that helps to control fluids and balance acids and bases in your blood. You get sodium from your diet and your kidneys flush it out when you have too much.

High serum sodium levels could signal dehydration or a problem with your kidneys.

Normal serum sodium levels are 135-145 milliequivalents per liter (mEq/L).

The researchers found that people with levels:

Those with levels between 138 and 140 were at the lowest risk of developing chronic disease.

Dehydration, just as the name implies, is a condition that occurs from either inadequate water intake, excessive water loss, or most commonly, both,” says Dr. M. Ramin Modabber, an orthopedic surgeon at Cedars-Sinai Kerlan-Jobe Institute in Los Angeles and the medical director and chief medical officer at Amgen Tour of California.

There are various degrees of dehydration ranging from mild to severe. Signs and symptoms vary based on the degree of water loss.

  • Common signs of mild dehydration include thirst and dry mouth, which can progress to moderate dehydration characterized by decreased or darker urine, headaches, and muscle cramps.
  • Severe dehydration symptoms include the inability to sweat or urinate and can be accompanied by dizziness, confusion, or fainting. This can be dangerous as vital organs can lose the ability to function normally.

“Whether it’s a cycling race or other strenuous activity you’re engaging in, being aware of the ways dehydration can strike and head it off at the pass are some of your best tools to stay healthy and active any time of year,” Modabber told Healthline.

There isn’t a “one size fits all” answer to how much fluid you should drink daily. Activity levels, medications, sweat production, health status, and temperature, especially when exercising, all affect how much fluid your body needs.

“Per the National Academies of Science, Engineering and Medicine (NAS)… the recommended guideline for adults is 125 ounces for men and 91 ounces for women per day,” says Dr. Neal Patel, DO, a family medicine specialist with Providence St. Joseph Hospital in Orange County, California. “This is based on gender. Someone with diarrhea or increased sweating due to high temperatures is at increased risk of dehydration and needs to consume additional fluids.”

“How much fluids someone needs is sometimes based on weight. Some calculations show that people should drink half their body weight in water,” he noted. “For example, if someone weighs 200 pounds, they should consume 100 ounces of water daily. People also consume about 20 percent of their liquid from foods.”

Older adults should be aware of other factors affecting water consumption:

It is essential to drink water and other fluids throughout the day, know the signs of dehydration, and start drinking water when symptoms first appear, experts say.

The most common reason for high sodium levels is a lack of fluids or dehydration.

The researchers noted that about half of the world’s population does not meet the recommendation for daily water intake. They recommend 6 to 9 cups for women, and for men, 8 to 12 cups per day.

The best way to prevent dehydration is to stay hydrated, which means drinking fluids throughout the day. However, sometimes that isn’t enough.

“Not all liquids are created equal,” says Patel. “For example, coffee is a diuretic, making you urinate out the water you consume. Juices high in sugar and alcoholic drinks are also more likely to make you urinate out more of your total water amount and increase your chance of dehydration.”

“I tell my patients that for every cup of coffee, you lose about a half-cup of water, and for every shot of hard liquor beverage they drink, you lose about 1 cup of water,” he added. “Therefore, my patients need to calculate their net water intake. Milk overall is not dehydrating and is neutral. Therefore, the amount of milk does not offset the water amount. I am not opposed to my patients drinking other beverages. Still, they should be mindful of how many cups of plain water they drink versus other drinks throughout the day.”

Another part of preventing dehydration is replacing the electrolytes lost through activity and exercise. Eating a well-balanced diet replenishes your electrolytes.

However, some foods are better for that than others, such as watermelon, strawberries, beans, and avocados. Many people use sports drinks to boost electrolytes lost through exercise, but knowing which ones are best can be challenging.

“To help you decide which electrolyte replenisher is right for you,” Modabber said, “we’ve ranked them below in order of those which get the job done on boosting electrolytes without including too much more of what you don’t necessarily need – especially added sugars.”

  • Coconut water Coconut water is a refreshing alternative to traditional sports drinks. It is lower in sugar and calories but contains potassium, magnesium, and sodium electrolytes. However, as with all electrolyte drinks, be sure to read ingredient labels. Beware of added sugars in flavored coconut water varieties.
  • Pickle juice While it might sound gross, pickle juice can be a great “quick shot” of electrolytes if you have been working out hard in the heat and need an electrolyte jolt but don’t have any other option handy. Pickle juice is high in sodium and has some potassium, and it likely won’t contain the sugar you don’t need.
  • Electrolyte-infused waters or electrolyte tablets They can provide a low-calorie and low-sugar alternative to higher-calorie and higher-sugar drinks like juices or traditional sports drinks. However, many marketed electrolyte drinks will throw in added sugars for carbohydrate rehydration, just like in sports drinks. So, be sure to read the labels.
  • Pedialyte Pedialyte is a common fluid hydration source used in medicine to fight dehydration from illness and is often associated with children. But it works just as well for adults and provides hydration and electrolytes, with more sodium and less sugar than in sports drinks.
  • Homemade electrolyte drinks It is possible to create an electrolyte concoction without buying something from the store or drinking lots of added sugar. Feel free to mix in water (regular or coconut), fruit juices, ginger, lemon, and sea salt. Including electrolyte tablets or powders provides additional benefits.
  • Smoothies Smoothies are an excellent post-workout electrolyte replenishment source, drawing nutrition from fruits, vegetables, dairy, and nuts. However, they are heavy and filling, making them difficult to take in during an intense workout.
  • Fruit juices Depending on the type of fruit juice, there are varying degrees of electrolyte benefits from different fruit sources. For example, watermelon juice is a good source of magnesium, potassium, and the amino acid L-citrulline. Orange juice and tart cherry juice provide potassium, magnesium, and phosphorus. However, most are low in sodium for electrolyte replenishment and high in sugar content, so it is essential to consider this when considering your replenishment needs.
  • Sports drinks Besides replenishing electrolytes and hydrating with fluids, sports drinks are meant to replenish carbohydrates quickly. They do this in the form of added sugars for quick absorption. This type of nutrient depletion generally only occurs with high-intensity exercise that lasts for an hour or more. So, if you’re exercising less intensely than this, sports drinks may be considered unhealthier sources of electrolyte replenishment.