How Much Water Should I Drink a Day?

How much water you should drink a day depends on your activity level, weather, and health status. The general recommendation is 11.5 cups of fluids per day for women and 15.5 cups of fluids per day for men. Food typically gives you about 20% of your daily water needs. This means that women actually need 9 cups of water per day, while men need 13 cups.

Water is essential to overall health. About 50% to 60% of your body is water. Keeping this level in balance through hydration is important.

Women need to drink about 9 cups of fluids per day, and men would need 13 cups. Factors like activity level, weather, and health status will affect the amount of fluid you lose and need.

Factors that impact how much water you need to drink include:

  • Breastfeeding: You will need more water than normal—as much as 16 cups of water a day—if you are breastfeeding. This amount can come from food and beverages. Drink a glass of water every time you nurse or pump to ensure you’re getting enough water.
  • Frequent exercise: You need more water than someone who is less active if you are an athlete or a frequent exerciser. Your exact needs depend on the type of exercise you are doing. The key is to drink water before, during, and after working out.
  • Higher elevations: You will tend to lose more fluid due to respiration, whether you regularly hike at high altitudes or live at a higher elevation. The higher your elevation, the greater the potential for fluid loss. Make sure you are prepared for this water loss, especially if it’s your first time at a higher elevation.
  • Hot weather: High temperatures can lead to dehydration and heat illness if you do not drink enough water. Drink before you get thirsty if you are working outdoors. Drink 8 ounces of water every 20 minutes.
  • Illness: Staying hydrated is an important part of the recovery process when you are sick. You can lose more fluid than normal if you sweat from a fever, have a runny nose, or have diarrhea or vomiting. Drinking water prevents dehydration.
  • Pregnancy: You may need to drink as much as 96 ounces of water per day when you are pregnant. Not only will this extra water aid in digestion, but it will help form the amniotic fluid around the fetus.

Your body depends on water to function. Water helps with:

  • Body temperature regulation
  • Joint lubrication and cushioning
  • Tissue protection
  • Waste removal through urination, sweat, and bowel movements

1. Fosters Memory and Cognition

Water makes up 75% of your brain mass. Not adequately replenishing the water you lose can have cognitive effects. Losing just 2% of your body’s water supply can cause short-term memory loss.

Water loss can also interfere with mental and physical performance, especially with regard to attention. Research has shown that children who stay hydrated throughout the school day have an increase in their ability to focus.

2. Helps Manage Weight

Drinking water can help you reach or stay in an ideal weight range. Water has no calories and supports fat loss through increased fat burning.

Consistent underhydration has been shown to increase body weight. Research has also shown that children who drink water rather than sugary drinks are less likely to be overweight.

3. May Help Prevent Heart Failure

Drinking enough water each day may reduce the risk of severe heart problems. One study found that staying hydrated throughout your life may slow the decline of cardiac function. Staying hydrated can also reduce heart failure risk.

4. May Promote Healthy Aging

Adults who drink plenty of fluids like water appear to have better health outcomes than those who do not drink enough fluids. One study looked at health data from more than 11,000 adults over a 25-year period. The researchers looked at people’s serum sodium levels, which can indicate how much water a person drinks. The higher the levels, the less fluid people have taken in.

People with higher serum sodium levels, meaning they were not as hydrated, had advanced biological aging. This group also had more conditions like heart and lung disease and were likelier to die younger. More research is needed to confirm these findings.

5. Might Reduce Risk of Type 2 Diabetes

Choosing water—or other unsweetened beverages—over sugary drinks can prevent type 2 diabetes. The risk reduction is not so clear if water is already your drink of choice. It happens when you replace sugar-sweetened beverages or fruit drinks with water.

6. Optimizes Exercise Capabilities

The most important thing you can do to improve your exercise performance is to drink enough water before you work out and replenish lost fluids afterward. Research has shown that drinking enough water can help you work out longer and at a higher intensity. Dehydration can detract from your performance—even when you lose just 2% of your body’s water stores.

7. Prevents Constipation

Constipation means having bowel movements fewer than three times per week. Your stool can be hard, dry, or lumpy and painful to pass. A lack of water or fluid intake is one of the most common causes of constipation. Stool moves through your digestive system more slowly when you are not properly hydrated.

Constipation will likely improve once you take in more fluids. Staying well-hydrated can prevent constipation in the first place.

8. Promotes Skin Hydration

You may consider drinking more water if you have dry or rough skin. Some evidence suggests that staying hydrated can reduce dryness and prevent premature aging. Keeping your skin hydrated may create the barrier your skin needs to prevent dryness and roughness.

You can get some water from the foods you eat. Your body also creates some water during metabolism, or the processes by which food is created into energy.

Here’s a look at the percentage of water in different foods:

Percentage of Water Food 
90-99% Cabbage, cantaloupe, celery, lettuce, spinach, squash, strawberries, and watermelon 
80-89% Apples, broccoli, carrots, grapes, oranges, pears, pineapples, and yogurt
70-79% Avocados, baked potato, bananas, cottage cheese, ricotta cheese, and shrimp
60-69% Chicken breast, legumes, pasta, and salmon
50-59% Feta cheese, hot dogs, ground beef, and steak
40-49% Pizza
30-39% Bagels, bread, and cheddar cheese
20-29% Biscuits, cake, and pepperoni
10-19% Butter, margarine, and biscuits
1-9% Cereals, crackers, dry-roasted peanuts, peanut butter, pretzels, and walnuts

You can become dehydrated when you do not drink enough water or lose more water than you take in. Dehydration can become life-threatening and cause complications like tachycardia (increased heart rate) or hypotension (low blood pressure). Even mild cases of dehydration can cause uncomfortable symptoms.

Adults

Symptoms of dehydration in adults can include:

  • Dark-colored urine
  • Dizziness
  • Dry mouth or skin
  • Increased thirst
  • Tiredness
  • Urinating and sweating less than usual

Your sensation of thirst declines as you age. Older adults might not be physically cued with thirst they need to drink water and often wind up drinking less than they need.

Infants and Children

It’s important to see a healthcare provider if your infant or child becomes dehydrated, especially if they have symptoms like:

  • Crying but not producing tears
  • Dry tongue and mouth
  • A high fever
  • Irritability
  • Not having a wet diaper for three hours or longer
  • Sleepiness or drowsiness
  • Sunken eyes

A group you do not need to give any water to is infants younger than 6 months. The recommended amount of human milk or infant formula is enough fluid. You can give infants up to 4-8 ounces per day when you start to give them food. You can increase your infant’s water intake after they are 1 year old. 

When To Get Immediate Medical Attention

Dehydration can become life-threatening. It’s important to get immediate medical attention if you have any of these symptoms:

Your kidneys can usually handle it if you overhydrate. Overhydration can lead to dangerous consequences, particularly if you have a condition that affects your ability to filter out water or makes your body retain water.

Excessive water intake can cause too much water and low sodium levels in the blood, or hyponatremia. It’s possible to have no symptoms or mild symptoms like lethargy. Severe overhydration may also cause confusion or seizures. 

Risk Factors

People who are more likely to overhydrate include athletes and people who drink excess water as part of a competition. Those who have psychogenic polydipsia may also overhydrate. Psychogenic polydipsia means being persistently thirsty despite having no physical condition to cause it.

Psychogenic polydipsia is most common among people with certain conditions, including:

Drinking water every day is essential to your overall health. The exact amount of water you need depends on how active you are, where you live, and your medical conditions.

Drinking the right amount of water can prevent heart disease and promote healthy aging. Just make sure you stay within typical recommendations. Drinking too much or too little water can come with serious consequences. Consider buying a water filter to remove contaminants if you are drinking water from the tap.

Health.com uses only high-quality sources, including peer-reviewed studies, to support the facts within our articles. Read our editorial process to learn more about how we fact-check and keep our content accurate, reliable, and trustworthy.
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