How much water should you drink a day?

People often hear that they should drink eight glasses of water per day. However, that may not be entirely true, and the amount of water a person should drink can vary depending on their age, activity level, and more. 

Water is an essential part of life, but how much should a person really be drinking? 

The commonly touted wisdom of eight glasses of water per day may be suitable for some people, but it is not a “one-size-fits-all” recommendation. 

Some experts say there is a lack of scientific evidence supporting these claims. Others note that promoters include bottled water manufacturers. 

So, how much water does a person really need? 

Recommended daily water intake 

Back in 1945, the U.S. Food and Nutrition Board advised people to consume 2.5 liters, or 84.5 fluid ounces (fl oz), of water per day, including fluid from prepared foods. Today, the Centers for Disease Control and Prevention (CDC) say there is no recommendation for how much plain water adults should consume daily. 

The 2015–2020 U.S. Dietary Guidelines do not recommend a specific daily water or fluid intake, but they do recommend choosing plain rather than flavored water and juices. 

Recommended intake by age 

There is no fixed amount of fluid recommended by age, but some patterns emerge among healthy individuals doing a moderate amount of activity in a temperate climate. 

The following sections show the average water intake for people of different ages. 

Infants—Experts do not recommend plain water for infants before the age of six months. 

The CDC says that if infants over six months of age need additional fluid on hot days, they can consume water in a bottle. However, their primary form of fluid and calories should be breast milk or formula. 

Children over 12 months of age—Children over 12 months of age should be encouraged to drink water 

as part of their daily routine (for example, after brushing their teeth and before, during, and after playtime at school) 

when the weather is warm 

as an alternative to sweetened drinks and juices 

Children should limit their juice consumption to one glass per day. 

Parents are advised to keep a pitcher handy to encourage healthy water-drinking habits, and schools should have water fountains or equivalent facilities. 

Adults ages 19-30 years— The recommended adequate intakes of total water from all sources each day for most adults between 19 and 30 years of age are: 

3.7 liters (or about 130 fl oz) for men 

2.7 liters (about 95 fl oz) for women 

People who are pregnant are likely to need an extra 0.3 liters (10 fl oz). Those who are breastfeeding will need an additional 0.7 to 1.1 liters (23–37 fl oz). 

Older adults—Older adults may be at risk of dehydration due to health conditions, medications, loss of muscle mass, reduction in kidney function, and other factors. 

Older adults who are well hydrated have been found to have: 

fewer falls 

less constipation 

a lower risk of bladder cancer, in men 

Dehydration has been linked to a higher frequency of:

urinary tract infections 


kidney failure 

slower wound healing 

Sources of water 

People can consume water by:

drinking water and other fluids 

eating foods high in water, such as fruits and vegetables 

Some surveys suggest that around 20 percent of water intake comes from food, and the rest is from fluids. This depends on diet. A higher intake of fresh fruit and vegetables will mean a higher intake of water from foods. 

Hydration during exercise 

During exercise, people may need to consume more water than usual. The amount they should drink depends on: 

the type and intensity of the activity 

environmental factors, such as temperature 

the size and muscle mass of the individual 

While it is important to be hydrated before a workout— and a person should aim to replace fluid lost after exercise—drinking water during a workout may not be essential. However, if people exercise for long periods, they may benefit from consuming water or an electrolyte beverage. 

When should a person drink water? 

Most of the time, the body’s sensitive natural mechanisms maintain appropriate fluid levels. 

There are two main ways the body does this: (1) through thirst, which tells a person to drink more water; and (2) through urine output, in which the kidneys regulate the water we consume by either emptying it into the urinary bladder or holding onto it in the blood plasma. 

The kidneys also regulate the balance of electrolytes, such as sodium and potassium, in the body fluids. Additionally, they receive hormonal signals to conserve or release water into the urine if the brain detects changes in the concentration of the solutes in the blood. 

What about eight 8-ounce glasses of water? 

It is often said that people need to drink at least eight 8-ounce (oz) glasses of water per day. However, this is an overly simplistic answer to a complicated question. 

The body is good at regulating itself and water is no exception. The body is constantly working to maintain a balance of water coming in and water going out. If a person drinks too much water, the body will excrete more. If they drink too little, it will excrete less. 

In addition to body size and activity level, other everyday factors can play a role in determining how much water a person should drink. 

For example, consuming more sodium and protein means a person may need to drink more water. Conversely, eating a lot of fruits and vegetables means they may not need to drink as much. 

Most of the time, the body will give a person clues that tell them to drink more or less fluid. The body even has a water-regulating hormone—arginine vasopressin—that manages thirst, fluid excretion, and the body’s water balance. 

Too much water? 

Some people have raised concerns that consuming too much water could be dangerous. If a person drinks too much water, it could lead to hyponatremia, or water intoxication, which is when sodium levels in the blood plasma become too low. 

Symptoms include: 

lung congestion 

brain swelling 


fatigue and lethargy 






Hyponatremia is rare. When it does occur, it usually affects endurance athletes, people with diabetes, and those taking certain medications. 

In summary, the amount of water a person needs varies based on their age, size, activities, and the temperature. Although many people follow the eight-by-eight rule, it may be outdated and overly simplistic. The body is incredibly good at maintaining its water balance, and it urges people to drink more by making them thirsty. 

People who work outdoors in hot climates or exercise vigorously may need to consume more water. They can also get fluid from foods high in water, such as fruits and vegetables. 

SOURCE: https://www. medicalnewstoday.com/ articles/306638?utm_ source=Sailthru%20 Email&utm_medium=Email&utm_ campaign=MNT%20Daily%20 News&utm_content=2021-11-19&api d=37763034&rvid=3424e32faa971 ce2c1b02d01eed1022831fc564614a d3f53b1cc99363570ba22 

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