Why Do We Need to Drink Water?
Water is one of the most important things our body needs every day. Even though we often hear that we should drink more water, many people don’t really know why it is so important for health. Water helps almost every system in the body work properly—from circulation to digestion and temperature control.
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| Why Do We Need to Drink Water? |
In fact, the human body is made of about 60–70% water, which shows how essential it is for survival. In this article, we’ll explain why drinking water is so important, how much you should drink, and what happens when you drink too little or too much.
Why Is It Important to Drink Water?
The answer is simple: our body needs water to function and survive. Every organ in the body relies on water to do its job properly.
Water Helps Maintain Blood Volume
Blood carries oxygen and nutrients to the brain, muscles, and other organs so they can produce energy and function normally.
Our cells absorb oxygen through the blood and release carbon dioxide (CO₂) when we breathe out.
Blood contains about 55% plasma, and plasma itself is about 90% water. This means that water makes up nearly half of our blood, which is why staying hydrated is so important.
Water Helps Maintain Saliva
Saliva contains about 90% water.
It helps us chew, swallow, and digest food. When food mixes with saliva during chewing, it becomes easier for the body to break it down and absorb nutrients.
Without enough water, the mouth can become dry, which makes eating and digestion more difficult.
Water Helps Regulate Body Temperature
The normal body temperature usually stays between 36.1°C and 37.8°C.
When the body gets too hot—because of exercise, fever, or hot weather—the body cools itself by sweating.
Sweat helps release heat and lower body temperature. But since sweating causes water loss, we need to drink regularly to replace the lost fluids.
8 Essential Benefits of Water for the Body
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Hydrating the human body
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Removing toxins and keeping the kidneys healthy
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Feeling full and supporting weight loss
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Improving the quality of skin and hair
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Helping the brain function properly
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Protecting joints and lubricating muscles
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Supporting easier and healthier digestion
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Regulating body temperature through sweating
Key Moments to Drink Water
1. When You Wake Up on an Empty Stomach
Drink a glass of water to kick-start your metabolism.
2. Before Each Meal
Drinking water before meals can help you feel fuller and prevent overeating.
3. During a Workout
Proper hydration helps you stay energized and maintain performance during physical activity.
4. Before Going to Bed
Drinking a small amount of water can help maintain hydration overnight.
Benefits Depending on Water Temperature or Type
Warm Water
Drinking warm water Can help relieve stomach pain or discomfort.
Lukewarm Water
Supports gentle digestion and healthy bowel movement.
Lemon Water
Often used for detox support and better nutrient absorption.
Sparkling Water
Has some benefits but should be consumed in moderation, especially for people with sensitive digestion.
Quick Answers to Your Questions
What Happens If You Don’t Drink Enough Water?
Not drinking enough water can lead to dehydration, which may cause fatigue, headaches, dry skin, dizziness, and poor concentration.
How Long Does It Take to Digest a Glass of Water?
Water is absorbed very quickly by the body, often within 5 to 20 minutes, depending on hydration levels and stomach contents.
What Are the Benefits of Drinking Salt Water?
Salt water may help replace electrolytes in certain situations, such as intense exercise or dehydration. However, it should not be consumed regularly unless recommended by a healthcare professional.
Water Helps Remove Waste Through Urine
Urine is made of about 95% water.
Its job is to help the kidneys remove waste and toxins from the body, including:
metabolic waste
medicine residues
substances the body doesn’t need
At the same time, the kidneys keep important minerals that the body still needs. Drinking enough water helps the kidneys work efficiently and maintain healthy body balance.
Water Helps Keep Skin Healthy
Skin health may not affect survival directly, but it still plays an important role in protecting the body.
The skin is actually the largest organ in the human body, and it contains more than 80% water.
Proper hydration helps:
keep skin soft and flexible
support cell renewal
protect the skin from dryness and early aging
How Much Water Should You Drink Each Day?
An average adult loses about:
1.5 liters of water through urine
about 1 liter through sweat, breathing, and bowel movements
Because of these losses, most health experts recommend drinking about 1 to 1.5 liters of water per day, in addition to the water we get from food.
Foods like fruits and vegetables can provide around 1 liter of water daily.
However, your water needs may increase depending on:
climate (hot weather)
physical activity
pregnancy or breastfeeding
illness or fever
3 Simple Ways to Estimate Your Water Needs
1. Replace What the Body Loses
An adult loses around 2.5 liters of water per day through urine, metabolism, and other functions.
Since food provides about 20% of daily water intake, we still need around 2 liters from drinks, such as water, soups, or other beverages.
2. The “8 Glasses a Day” Rule
A simple guideline is to drink 8 glasses of liquid per day.
If each glass contains 250 ml, this equals about 2 liters of water, which meets most daily hydration needs.
3. Nutrition Recommendations
Some nutrition experts suggest drinking about 30 ml of water per kilogram of body weight.
For example, a person who weighs 70 kg would need about 2.1 liters of water per day, including fluids and water from food.
If someone has a fever above 38°C, it is usually recommended to drink an extra 0.5 liter of water for each degree above 38°C.
EFSA Recommendations
According to the European Food Safety Authority (EFSA), food provides about 20% of total daily water intake.
Based on this estimate:
Men should drink about 2 liters of water per day
Women should drink about 1.6 liters per day
When Should You Drink Water?
It is better not to wait until you feel thirsty before drinking.
A good habit is to drink small amounts regularly throughout the day. Drinking small sips is usually easier on the stomach than drinking large amounts at once.
Pregnant women who experience nausea may feel better if they avoid drinking during or right before meals.
Water and Exercise
The American College of Sports Medicine recommends:
drinking about 500 ml of water two hours before exercise
continuing to drink regularly during physical activity
Cool water between 15°C and 22°C is usually ideal.
If exercise lasts longer than one hour, a sports drink containing carbohydrates, sodium, and potassium may help replace nutrients lost through sweat.
What Happens If You Drink Too Much Water?
For most people, drinking a little extra water is not harmful.
However, drinking more than 5 liters per day without intense exercise can reduce sodium levels in the blood, a condition called hyponatremia.
In rare cases, this can cause serious problems such as brain swelling.
Excessive thirst and very high water intake may also be a sign of diabetes, so it is important to consult a doctor if this happens.
What Happens If You Don’t Drink Enough Water?
Not drinking enough water can lead to dehydration.
Losing just 1% to 2% of body weight in water already means the body is dehydrated.
Common signs include:
dark urine
dry mouth
dizziness
fatigue
dry skin
Severe dehydration—when water loss reaches 15–20% of body weight—can be life-threatening.
Babies and older adults are especially at risk because they can lose fluids quickly or feel less thirst.
Conclusion
Water plays a vital role in almost every function of the human body. It helps carry oxygen and nutrients, regulate body temperature, remove waste, support digestion, and maintain healthy skin.
Drinking enough water every day is one of the simplest ways to support your overall health. By making hydration a regular habit—especially during hot weather or physical activity—you can help your body stay balanced, energized, and functioning properly.
📚 Medical Sources
World Health Organization (WHO). Nutrient requirements and recommended dietary intakes for water. https://www.who.int
European Food Safety Authority (EFSA): Scientific Opinion on Dietary Reference Values for Water. EFSA Journal. https://www.efsa.europa.eu/en/efsajournal/pub/1459
Mayo Clinic. Water: How much should you drink every day? https://www.mayoclinic.org
U.S. National Academies of Sciences, Engineering, and Medicine: Dietary Reference Intakes for Water, Potassium, Sodium, Chloride, and Sulfate.
American College of Sports Medicine: Exercise and Fluid Replacement Guidelines.
