How Much Water Should You Drink?

Drinking water helps you stay hydrated and ensure your body can function properly, but exactly how much water should you drink? Here is a breakdown of hydration facts and some simple to help you keep your fluid intake up.

Health Benefits of Drinking Water

Water is an essential nutrient and proper hydration is vital for optimal health. Water accounts for roughly 60% of total body weight and it plays an important role in energy, mood, performance, and body composition ⁽¹⁾. For instance, water helps to ^{(2, 3)}:

• Move nutrients and oxygen to cells
• Flush waste from the body
• Regulate body temperature
• Normalize blood pressure
• Cushion organs
• Protect joints
• Maintain electrolyte balance (sodium levels)
• Lower your risk of dehydration and heat stroke
• Improve skin health

Factors that Affect Water Intake

Exactly how much water you should drink depends on a host of genetic and lifestyle factors, including:

• Weight: Body size influences water intake as larger bodies will require more water than smaller bodies.
• Genetics: Some individuals naturally sweat more than others and will, therefore, require more water to replenish lost fluids.
• Activity Level: Individuals with manual jobs or who exercise more regularly will require more water than sedentary individuals. Water needs generally increase with the intensity and duration of exercise.
• Climate: Temperature and humidity play a large role in water intake, as hotter and more humid environments typically require higher water intake.
• Location: Altitude can also affect water intake as the lower oxygen levels at higher altitudes can lead to faster water loss through increased breathing and urination ⁽⁴⁾.
• Diet: A diet higher in processed food might require more fluids than a diet rich in whole foods, as many whole foods naturally contain more water. Moreover, diets with higher carbohydrate and sodium intake can affect your hydration needs.
• Medication: Certain medications can affect water needs.
• Pregnancy and Breastfeeding: Women who are pregnant or breastfeeding have greater water needs.

For example, larger individuals who exercise regularly in hot conditions require more water than smaller individuals who are sedentary in cooler climates.

How to Calculate How Much Water to Drink a Day

Given that hydration needs vary greatly from person to person, there is no one-size-fits-all recommendation for water intake. While there are some general guidelines for daily fluid intake, it’s important to understand that they are simply that, guidelines.

In fact, the very popular “8×8” recommendation to drink eight 8-ounce glasses of water a day has little scientific evidence to support it, and the “1 ounce of water per pound of body weight” calculation commonly used in the bodybuilding community is merely a suggestion.

While different health bodies provide different guidelines, on average, it is suggested that the total water intake for men is 15.5 cups (3.7 liters) per day, and the total water intake for women is 11.5 cups (2.7 liters) per day ^{(5, 6, 7)}. These estimates, however, include water consumed from foods and beverages.

Interestingly, data shows that many Americans are not drinking enough water. A US National Health and Nutrition Examination survey found that children and adolescents have an average daily water intake of 23 ounces (3 cups), while adults have an average daily water intake of 44 ounces (5.5 cups), missing the dietary reference intakes ⁽⁸⁾.

How do you know if you’re drinking enough water?

Here are some questions you can ask yourself to know if you’re drinking enough water:

• Do you feel thirsty? If you feel thirsty or have a dry mouth, you need to drink more water. Thirst is generally a sign that you’re already slightly dehydrated, while rare thirst is a sign you’re adequately hydrated.
• What color is your urine? Urine color is a strong indicator of hydration levels. A dark yellow urine color is a sign that you’re not getting enough fluids and need to drink more water. A light yellow urine color is a sign that you are properly hydrated. The amount of urine you produce is also a sign of hydration status. If you’re not producing much urine and it’s dark in color you need to drink more water.
• How’s your mood? Headaches, dizziness, fatigue, and weakness are all potential signs you’re dehydrated.

What Contributes to Water Intake

While water intake is generally thought of as plain drinking water, our total water intake includes drinking water, water in beverages, and water that is part of food. Approximately 80% of our daily water intake comes from beverages, while the other 20% usually comes from foods ⁽⁹⁾. Here are some examples of foods and beverages that contribute to water intake:

• Plain Water
• Sparkling Water
• Milk
• Juices
• Coconut Water
• Smoothies
• Coffee and Tea
• Sports Drinks
• Fruits and Vegetables
• Soups and Broths
• Yogurt and Cottage Cheese

Although caffeinated beverages are often considered dehydrating, studies have shown that coffee, tea, soda, and diet soda are equally as hydrating as water ⁽¹⁰⁾. While this might be surprising, these beverages are mostly water, particularly coffee and tea, and even though sugary drinks and soda are in no way considered “healthy” beverages due to the added sugar and additives, they are also mostly water.

Based on the research, it seems only when we approach caffeine intake of 6mg/kg or over 500mg of caffeine from coffee do we see increased urine output compared to water ⁽¹¹⁾.

Tips to Increase Water Intake

While most people know water is important, many are still missing their optimal daily water intake. Here are some simple tips to help you drink more water.

1. Drink it before anything else. Before you reach for your morning coffee or smoothie, drink a large glass of water to help the body rehydrate from sleep and set the tone for the day.
2. Carry a water bottle. Make drinking water convenient and obvious by keeping a water bottle with you throughout the day.
3. Make it routine. Associate drinking water with specific times or daily activities to create rituals around hydration. For example, drink a glass of water before meals, on your way to the gym, or while you’re watching TV at night.
4. Set reminders. If you struggle with drinking water, set alarms on your mobile phone throughout the day to remind yourself to grab a glass of water when you get busy.
5. Enjoy hydrating foods. Remember that water intake comes from more than just plain water. Consuming a diet rich in hydrating foods, such as cucumber, lettuce, and watermelon, water-rich foods, such as soup, and healthier drinks, such as smoothies and hydrating cocktails, can all help to increase your water intake.

The Bottom Line

About 60% of your body is made up of water and proper hydration is essential for optimal health. How much water a person requires depends on several genetic and lifestyle factors including weight, genetics, activity level, climate, environment, and diet. On average, the total water intake is 15.5 cups (3.7 liters) per day for men and 11.5 cups (2.7 liters) per day for women and includes water from plain water, beverages, and foods.