There is no straightforward answer to this question. Even studies over the years have produced varying recommendations. But the fact is, you need to drink enough water every day to stay hydrated. So how much water is enough per day?

While drinking water depends on various factors, many health experts recommend drinking 8-ounces of glasses, which is equal to half a gallon or two liters. This is called the 8*8 rule. Other experts will tell you to drink as much water as possible even when you are not dehydrated.

Do I Really Need to Drink 8 Glasses of Water Each Day?

One hears it everywhere: drink eight 8-ounce glasses of water a day. But just where did that idea come from, and is it really necessary for good health?

Water is a very important component of a healthily functioning body, no doubt about it. But when it comes to just how much water one should drink on a daily basis, it’s a little bit harder to find an answer. In recent years, the rule of 64 ounces (or eight 8-ounce glasses) of water each day, has become the accepted standard, but research has proven that claim is not necessarily as solid as some have been led to believe.

The Origin of Eight Glasses a Day

drinking water

While there is no concrete evidence supporting just where this idea first came from, many people believe that the trend stemmed from a statement made by the Food and Nutrition Board of the National Research Council in 1945.

The Board recommended one milliliter of water for each calorie of food, which equals roughly 64-80 ounces. However, what many people fail to realize about this recommendation is that the amount is for total water intake, including what one may obtain from foods and other beverages.

Factors that influence water needs

drinking water

Here are some of the factors that may impact your total fluid intake:

  • Your overall health: When vomiting, have diarrhea or fever, your body loses a lot of fluid. You are also likely to lose more fluids when you have a bladder infection and urinary tract stones. If you have any of this condition, you will need to hydrate often.
  • Exercise: Do you do activities that make you sweat a lot? If yes, you need to drink extra water to replenish the lost water. It is wise to drink water before and after exercising for your body to be adequately hydrated.
  • Environment: During hot days your body will need more water to cover for fluid loss. Dehydration is also common at high altitudes.
  • Pregnancy or breast-feeding: Pregnant women and those breasting feeding need extra water to stay hydrated. It is recommended for pregnant women to drink 2.4 liters of fluids daily and about 3.1 liters per day for breasting women.

So, How Much Water Does the Body Need?

drinking water

So, if a portion of one’s daily water needs can be obtained from drinking juice, tea, and from food, then just how much water does one need to drink on a daily basis? There really is no magic number that applies across the board. Just as daily calorie needs vary due to activity level, age, and other factors, the daily water intake varies as well. The amount may be higher for individuals who live in warmer, drier climates, are more physically active, or suffer from certain health conditions, while those whose daily activity level is lower may not need to drink quite as much water.

The general rule is that one should take in enough water to replace what is lost every day through perspiration and other bodily functions. According to the Mayo Clinic, that number is somewhere around 10 cups of water. Replenishing that loss can come from pure water, other beverages, and foods, and may be higher or lower depending on the individual.

So when striving to keep the body hydrated, keep in mind the fact that 64 ounces of water is simply a rule of thumb amount, not a rigid standard. There is no conclusive evidence that drinking 64 ounces of water a day results in better health. While it is extremely important to keep the body properly hydrated, listening to ones own body, taking into account personal activity levels, and keeping track of the amount of water received from other sources can be more effective for proper hydration than following the 8-glass standard.

Health benefits of water

drinking water

Water is an essential component in your body. It is about 60% of your body weight. Basically, our bodies depend largely on the water to function properly. Here is how water benefits your body:

  • Gets rid of wastes through perspiration, urination, and bowel movements
  • Lubricates and cushions joints
  • Keeps your temperature normal
  • Protects sensitive tissues

How can you tell if you are drinking enough water?

The color of your pee can tell whether you are drinking enough water or not. If your urine looks dark yellow and infrequently urinating, you are not hydrated enough. It is normal to pee every 90 minutes to 2 hours. Frequently urinating is an indicator you are taking too much water, and it likely that water is not benefiting you. Frequent urination can also signal that you need to see a doctor ASAP.

Skin hydration can also tell you if you are hydrating well. You can tell the level of your skin hydration by pinching the skin on the back of your hand for a few seconds. If the skin returns back to normal quickly, you are probably well hydrated. If it takes longer to return, you are probably dehydrated.

Other symptoms of dehydration include:

  • Confusion
  • Fatigue
  • Brain fog
  • Dizziness

No one will tell you whether you have taken enough water at the end of the day, only you can know if you had enough. To be sure you are drinking enough water every day, consider experimenting until sure of what works best for you. You can do the following to hydrate your body well:

  • Drink water when you are thirsty
  • Avoid drinking more once you quench your thirst. Your body doesn’t need more water to function properly.
  • Drink enough water when exercising and during hot and dry days

Does water intake affect energy levels and brain function?

energy level

Various studies have shown how water intake affects energy levels and brain functions. One showed that fluid loss of 1.36% after exercising increase the frequency of headache and impair mood and concentration.

Other studies further revealed that mild dehydration caused by exercise heat affects various aspects of the brain function (* * *).

Mild hydration has also been linked to poor physical performance and reduced endurance (* * *).

As you can see, loss of fluid can result in some adverse effects on both your mental and physical performance.

Does drinking water help in weight loss?

weight loss

Drinking enough water has been linked to weight loss and especially when combined with a healthy diet. Some studies show that taking about 500 ml of water can temporarily boost metabolism by 24-30%.

Additionally, drinking cold water is beneficial because your body is forced to burn more calories to heat the water to the body temperature. Don’t forget drinking water reduces the amount of calorie intake and especially in older adults (* *). In fact, there is a study that revealed dieters who drink 500 ml of water before a meal can lose 44% more weight in 12 weeks than those who don’t.

Does drinking water help prevent health problems?

Yes, drinking enough is very beneficial in many ways. Here is where drinking enough water is crucial

  • Increased water intake stops constipation (* * *).
  • Increased water intake lowers the risk of bladder and colorectal cancer (* * * *).
  • Drinking enough water lowers the risk of kidney stones (* *).
  • When you drink enough water, your skin is well hydrated, and that reduces the risk of acne.

Do other fluids contribute to fluid balance?

Other fluids also contribute to fluid balance. So, feel free to gulp them anytime. But remember some fluids have their drawbacks. For example, coffee, alcohol, and tea are diuretic. Remember also to avoid drinks with a high amount of sugar, extra calories, and salt as you may end up hurting your health.

Food loaded with water also contribute to fluid balance.

Easy way to drink more water


Having trouble drinking enough water? Here is what you can do to drink more:

  • Infuse water with fruits
  • Drink flavored seltzer water
  • Eat water-dense food. Below are some fruits with high water content you can try:
  • Coconut water (95% water content)
  • Watermelon (92% water content)
  • Grapefruit (91% water content)
  • Strawberries (91% water content)
  • Cantaloupe (90% water content)
  • Peach (88% water content)
  • Raspberries (87% water content)
  • Oranges (87% water content)
  • Pineapple (87% water content)

Water-rich vegetables include:

  • Iceberg lettuce (96% water content)
  • Celery (95% water content)
  • Cucumber (95% water content)
  • Romaine (95% water content)
  • Tomatoes (94% water content)
  • Zucchini (94% water content)
  • Spinach (92% water content)
  • Cabbage (92% water content)
  • Green peppers (92% water content)
  • Cauliflower (92% water content)

You can also stay hydrated by taking soup, smoothies, stews, slushies, chilis, and popsicles, but it is good to avoid fluids with too much salt and sugar.