Health Benefits of Drinking Water


A woman drink a glass of water

A woman drink a glass of water

JLco – Ana Suanes / Getty Images

You need water for virtually every process in your body. Water plays a role in keeping your temperature normal, lubricating joints, protecting your spinal cord, and eliminating waste from your body.

Drinking enough water also prevents dehydration, a state you reach when you don’t have enough fluids in your body that can cause a variety of symptoms like mood changes, kidney stones, and constipation.

Some of your day’s water intake comes from the food you eat or other liquids you drink. But regular water offers all the benefits with none of the calories, sugar, or other potential drawbacks of some of the other water sources.

Prevents Headaches

Dehydration can cause headaches on its own. Dehydration can also lead to headaches by worsening underlying issues like headache disorders, such as migraine, or conditions caused by body fluid imbalance.

A 2020 study of women ages 18-45 found that the more dehydrated the women were, the more severe their migraine symptoms were. Dehydration was also associated with worse headache pain over a longer period of time and led to more frequent migraines.

Drinking water can stave off headaches brought on by dehydration.

Signs and Symptoms of Dehydration

Helps Prevent Chronic Conditions and Faster Aging

Staying adequately hydrated may slow down the aging process, prevent chronic conditions, and even help you live longer. Authors of a 2023 study determined this after analyzing people’s serum sodium levels. The levels of sodium in your blood tend to increase when you are not as well hydrated. In the study—which looked at 15,752 people over 25 years—people with higher levels of serum sodium tended to have worse outcomes.

The study found that people ages 45 to 66 with higher serum sodium levels were more likely to have signs of faster aging. Higher serum sodium levels were also associated with earlier death and the development of chronic conditions. 

Higher serum sodium levels were found to be related to a higher risk of the following conditions:

  • Dementia
  • Diabetes
  • Chronic lung disease
  • Heart failure
  • Stroke
  • Atrial fibrillation, an abnormal heart rhythm

Meanwhile, proper hydration was associated with a lower risk of several chronic conditions.

Decreased hydration is one of the main factors that elevates serum sodium. More research is needed to say for certain whether hydration, serum sodium, chronic conditions, aging, and death are all directly related.

Helps Manage Weight

Drinking water may help people who are overweight or who have obesity meet whatever goal weight a healthcare provider has set.

A 2019 review of studies found an average weight loss of 5% among people who upped their water intake. People in the six trials included in the review either drank water before meals, replaced caloric beverages with water, or drank more water every day. The most effective method for weight loss was replacing calorie-containing beverages with water.

Once whatever recommended weight has been lost—or if you’re already within your recommended range—drinking water can then help you maintain your weight.

Improves Concentration

It can be hard to concentrate when you’re dehydrated. You may have headaches, or your brain may not be functioning at optimal levels. After all, your brain is up to 75% water.

A 2020 study of more than 2,500 adults older than 65 found an association between hydration and mental performance among women. In the study, women who were better hydrated tended to perform better on tests of attention and processing speed.

In a small 2020 study of Chinese young adults, going without water for 12 hours led to impaired memory. Drinking 17 ounces (oz) of water was enough to improve memory.

May Improve Mood

When the young adults in the 2020 Chinese study hadn’t had water in 12 hours, they felt fatigued and angered. However, once they drank 17 oz of water, their mood improved.

A 2018 study of 3,327 Iranian adults also found that drinking water was associated with better mood. The researchers found that the more water people reported drinking, the less likely they were to report being depressed. People who drank 2 cups or less of plain water a day were twice as likely to be depressed than those who drank more than 5 cups daily.

Improves Athletic Performance

Adequate hydration is important for everyone, including athletes. Drinking water can help athletes with:

  • Performance
  • Post-exercise recovery
  • Injury prevention

Not getting enough water has been shown to cause dips in endurance and strength. The amount you need varies by your activity level. It’s generally recommended to be well hydrated before exercise, to drink during extended exercise, and to rehydrate after you’re done.

Nutrition of Water

In general, 8 oz of plain bottled water contains:

  • Calories: 0 grams (g)
  • Fat: 0 g
  • Sodium: 4.8 milligrams (mg)
  • Carbohydrates 0 g
  • Fiber: 0 g
  • Added sugars: 0 g
  • Protein: 0 g

The mineral content, such as calcium and magnesium, can change depending on the brand.

Risks of Water

It’s hard to drink too much water, but it can happen. In rare cases, people may develop water intoxication, which is when you drink more water than your kidneys can process. Water intoxication is most frequently reported in relation to water-drinking contests. The condition can cause seizures, delusions, coma, or death.

It’s also possible for water to get contaminated and for you to get sick after drinking contaminated water. The US Environmental Protection Agency regulates public water systems, so tap water is typically safe to drink. However, germs or chemicals can be in tap water at levels high enough to make you sick. When this happens, your water utility company will notify you. The company will also send out an annual report on your water’s safety. If you have a private well, you have to check water safety levels yourself.

Editor’s Note: You can drink tap water, filtered water, or choose from several types of bottled water, including:

  • Artesian well water, which is water from an aquifer below the surface
  • Mineral water, which contains minerals and trace elements from the water source itself
  • Spring water, taken from a natural spring arising from an underwater rock formation
  • Well water, collected from a hole bored into the ground to an underground source

Some bottled water may also be tap water or municipally treated water. 

Tips for Consuming Water

Guidelines vary for how much total fluid to get per day, ranging from 2 to 2.7 liters (l) of fluid a day for women and 2.5 to 3.7 liters a day for men. Those amounts are for fluid of any type, including fluid from food.

There’s no current recommendation for how much plain water to drink a day. But know that you only get 20% of your daily water needs through food—the other 80% would be from beverages, including plain water. 

To get the water you need, try these tips: 

  • Carry a water bottle and refill it throughout the day. 
  • Freeze a few water bottles so you have cold water throughout the day.
  • Swap out sugary drinks for water.
  • Order water when eating out or serve it during home-cooked meals. 
  • Add a lemon wedge to your water for more flavoring.

Try to never get to the point where you are thirsty. Pay attention to body cues and, if you realize you are thirsty, have water. If you are someone who needs more water, maybe because you live in a hot climate or take certain medication that requires it, make sure you drink the amount you need to avoid dehydration. 

A Quick Review

Everyone needs water to function properly. Water provides many health benefits, including preventing headaches and chronic conditions. Water can also improve mood, concentration, and athletic performance. With 0 calories and no sugar, water can be a great substitute for other drinks. Swapping out other drinks for water when you are at home or eating out is one way to take in more water. You can also carry a refillable water bottle so you can drink more water throughout the day and reap its many benefits.