In this article:
- Pure water has no taste or smell. Water has a pH level of 7 and is free of calories.
- At birth, 80% of an infant’s body weight is water.
- The initial weight loss after an intense physical activity is attributed to water loss, not fat loss.
- Water comprises 71% of the Earth’s surface and can be broken down into the following uses: 97% is salty or undrinkable water, 2% is locked in glaciers and ice caps, 1% is present for human needs such as agricultural, residential, manufacturing, community, and personal needs.
Despite the fact that water lacks any calories or organic nutrients, it is vital for all forms of life. Accounting for 60% of the human body, water is essential for cellular homeostasis and a wide variety of biological processes including. (1)
- Fueling the body with oxygen delivery
- Regulating temperature
- Lubricating joints
- Gastrointestinal health
It has been found that humans are capable of surviving without food for 2 weeks but cannot survive without water for only 2 days. Water has been referred to as the “elixir of life” as it is the cornerstone that allows human existence and survival.
Water and the Human Body
Water is a major constituent of various body parts and is present in the following amounts:
- Brain and heart – 73% water
- Lungs – 83% water
- Skin – 64% water
- Muscles and kidneys – 79% water
- Bones – 31% water
At birth, babies are composed of 78% water and this decreases to 65% by age 1.
Adult men and women contain slightly different amounts of water due to differences in body composition. Women tend to carry more fat, which contains less water than lean tissue.
Thus, bodies of adult women are composed of 55% water, whereas bodies of adult men are composed of 60% water.
What Increases Water Needs?
Your body’s water requirement increases in these conditions:
- Diarrhea or vomiting
- Physical activity or exposure to warm/hot conditions
- Replace fluids lost through sweat. With excessive sweating, drinks rich in sodium are recommended. (1)
- Consuming a high-protein diet (to help promote proper kidney function)
- Consuming a high-fiber diet (to prevent constipation)
What Role Does Water Play in the Body?
Water is a vital component in the human body as it fulfills these functions:
- Maintains temperature
- Lubricates the joints
- Protects the spinal cord and sensitive tissues
- Promotes a healthy digestion
- Assists in the removal of waste via urination, perspiration, and bowel movements
- Assists in the transportation of nutrients and oxygen to cells
- Promote normal blood pressure and stabilizes the heartbeat
- Promotes normal saliva production
- Moistens the mucous membranes in the lungs and mouth
- Assists in maintaining proper electrolyte balance
Benefits of Drinking Water
Drinking enough water is beneficial to the body in several ways.
1. Maintains a Healthy Digestion
Water is a vital component that ensures the proper function of the gastrointestinal tract. Sufficient water intake improves the body’s ability to break down food, hence promoting a smooth-functioning digestive system. It prevents constipation as well as reduces gas and bloating.
When the body has inadequate water supply, the colon absorbs water in an effort to hydrate the body. This often results in an altered fluid balance in the gut and constipation.
Constipation is complex and is influenced by dietary factors, drinking habits, a sedentary lifestyle, and side effects of medication. Drinking adequate water allows the digestion and metabolism in the gut to be more efficient.
Water can also help reduce heartburn, which is a very common gastrointestinal symptom.
A randomized control study found that hydrogen-carbonate-rich mineral water was effective in alleviating heartburn frequency and severity. Hydrogen carbonate is alkaline in nature and therefore can reduce the acidity in the stomach. (2)
2. Aids in Weight Management
It is widely accepted by the general public, although with little evidence, that increasing water intake is a good strategy to promote weight loss. Water can help reduce weight in a variety of ways:
- Water consumption boosts metabolism.
- Water helps suppress the appetite and promote satiety, leading to a decrease in caloric intake.
- Water can promote the breakdown and metabolism of fat cells.
- Water can substitute calorically dense and sugary beverages. (9)
3. Promotes Proper Kidney Function
In order to work properly and efficiently, the kidneys require adequate fluids to clear the unwanted wastes from the body. Water acts as a medium to flush out the toxins from the body via sweat and urine.
4. Promotes Healthy Skin
Remaining hydrated helps keep the skin hydrated and improve capillary blood flow to support healthy and young-looking skin. Conversely, a dehydrated state thickens the blood and dries out the skin.
The associations between the daily amount of consumed water, skin hydration, and skin physiology are receiving more attention in terms of increased clinical studies.
One systematic review found that the extensibility and elasticity of the skin increased slightly with a hydrated state.
It has also been found that water intake may increase stratum corneum hydration, which is the outer layer of skin. (12) Water also helps prevent or even treat soft lines, scars, acne, and wrinkles. (13)
5. Reduces Risk for Urinary Tract Infections
Urinary tract infections (UTI) occur when bacteria moves from the bladder to the urethra to contaminate the genitourinary system. UTIs are associated with low fluid intake and output as well as increased urine osmolality and acidity. (16)(17)
Women are more prone to UTIs because they have shorter urethras than men.
- Increased fluid output can help dilute the effect of the contaminating bacteria.
- Adequate fluid intake can help maintain optimal urine pH and prevent it from becoming more acidic
A randomized clinical trial assessed if increased hydration could help prevent recurrent cystitis. It was found that increased daily water intake over 1 year decreased the frequency of cystitis by 50%. (14)(15)
6. Treats Headaches and Migraines
Staying hydrated helps you become more alert, composed, and focused, ultimately improving your productivity. An inadequate fluid status can have the opposite effect, triggering headaches or migraine episodes.
A randomized control study that included people suffering from at least two moderately intense headaches a month or five mildly intense headaches a month assessed the impact of drinking more water. (19)
It was found that 47% of those who drank more water had significant improvement in headache intensity compared with 25% in the group that did not drink more water. Water did not seem to have a relevant impact on the length of moderate headaches. (19)
Headaches that occur due to dehydration are best treated and prevented in the future by consuming an adequate amount of water daily.
7. Relieves Fatigue
Fatigue is one of the first detectable symptoms of dehydration.
When the human body suffers from dehydration, it experiences a decrease in blood volume. As a result, pumping oxygenated blood throughout the body becomes more difficult and less efficient.
This extra work on the body can lead to fatigue.
8. Helps Alleviate Mood
Mild dehydration is a fluid loss of 1%-3% that is not replaced. This loss is found to negatively impact the brain, impairing the mood, concentration, and memory. (20)
Remaining in a hydrated state promotes proper brain function. A study found that when dehydration decreased body mass by more than 2%, mood was greater influenced, fatigue was greater, and alertness was lower. (20)
An inverse relationship was also found between plain water consumption and depression. (21)
More studies are warranted to better establish the relationship between depression, anxiety, and water consumption.
However, it is safe to say that adequate water consumption daily can help improve mood when one is feeling low.
Water also appears to have the following effects that need more evidence to validate:
- Helps rehydrate the body and control hangovers
- Assists in stress relief
- Improves foul-smelling breath
- Assists in staying physically active
Tips on How to Drink More Water
If you do not drink water often, follow these tips to conveniently develop this healthy habit:
- Keep a water bottle or glass of water nearby at all times.
- Pour a glass of water to consume with food intake, whether during meals or snack time.
- For every cup of coffee or tea consumed, pour a glass of water to sip on as well.
- Each time you use the restroom, stop to drink some water.
- Drink 1 glass of water before and after bed.
- Add ice cubes to your water to make it more refreshing.
- Infuse your water with fruits and/or herbs to give it a subtle flavor.
- Consume sparkling water instead of soda or juice.
- Monitor your water intake by using a water bottle that is marked.
- Mobile apps are available to help track your water intake.
- Set goals for how much and how often you want to drink water throughout the day.
How Much Water Do You Need?
Because the human body is not capable of storing water, it is necessary to make up for losses of water from the lungs, skin, urine, and feces. The amount of water needed is dependent on various factors including:
- Food consumed
- Activity levels
Daily fluid intake is the amount of water consumed from food, drinking water, and other beverages. Most healthy people are able to meet their daily fluid needs by listening to their body, as it signals for thirst and hunger.
General set guidelines for daily fluid intake are made based on gender:
- Women – recommended to consume 91 ounces of water daily (from food and beverage)
- Men – recommended to consume 125 ounces of water daily (from food and beverage)
It is found that 80% of total fluid intake is obtained from drinking water and other beverages that often contain caffeine. The other 20% of fluid needs is obtained from food intake.
Sources of Water
Despite the well-known benefits of water consumption, drinking it regularly is often overlooked by people. Water can be obtained from various sources, including the following:
- Water is present in food, and water is produced during the process of metabolizing food.
- Up to 20% of daily water needs can be met through food sources.
Liquid foods and beverages
- Soup, milk, tea, coffee, soda, drinking water, and juice are also sources of water.
- Although alcohol contains water, it is a diuretic, which means it increases urine production and thus promotes water loss.
Water Content in Different Food Items
The amount of water in the following food items include. (25)
|Percent of Water Present||Sources|
|90%-99%||Fat-free milk, cantaloupe, strawberries, watermelon, lettuce, cabbage, celery, spinach|
|80%-89%||Fruit juice, yogurt, apples, grapes, oranges, carrots, cooked broccoli, pears, pineapple|
|70%-79%||Bananas, avocados, cottage cheese, ricotta cheese, baked potato, cooked corn, shrimp|
|60%-69%||Pasta, legumes, salmon, ice cream, chicken breast|
|50%-59%||Ground beef, hot dogs, feta cheese, cooked tenderloin steak|
|10%-19%||Butter, margarine, raisins|
|1%-9%||Walnuts, dry-roasted peanuts, chocolate chip cookies, crackers, cereals, pretzels, peanut butter|
Excessive Water Loss: Dehydration
Water losses are normal for the human body through sweat, tears, breathing, urine, and bowel movements. Typically, healthy individuals are able to replace these losses through the consumption of fluids and foods in which water can be derived from and remain hydrated.
Individuals who suffer from a fever, diarrhea, vomiting or overexposure to heat are at higher risk for dehydration due to excessive losses in water that are not being replaced adequately.
Symptoms of dehydration include:
- Dark-yellow and concentrated urine
- Dizziness or lightheadedness
- Dry mouth, lips, and eyes
If you experience such symptoms, drink fluids. You may need to consult a medical professional for IV fluids to rehydrate.
What Is Overhydration?
Overhydration, also known as water intoxication, is a rare phenomenon that occurs when the consumption of water is much higher than the losses of water.
Overhydration causes an imbalance of sodium and other electrolyte levels. Hyponatremia occurs because sodium levels become diluted in the bloodstream. (23)
Also, water starts to leave the bloodstream to enter the cells, causing swelling. Such swelling requires immediate medical treatment, especially if occurring in the brain.
It is difficult to identify overhydration in early stages as symptoms include:
- Altered mental status
If not detected and severe hyponatremia occurs, seizures, coma, or death can occur.
What is a full liquid diet?
Full liquid diets are composed only of fluids or foods that are liquid at room temperature. Full liquid diets are less restricting than clear liquid diets, as they include dairy products.
Clear and full liquid diets are often recommended before or after certain types of surgery and are not recommended for long-term use.
Where does drinking water come from?
Drinking water is supplied to homes from two sources:
- Surface water: Collected from streams, rivers, lakes, or reservoirs.
- Groundwater: Collects in spaces within rocks or underground aquifers. Obtaining the water requires drilling wells and pumping water to the surface.
Public water systems obtain water from both sources.
What happens if you do not drink enough water during pregnancy?
Pregnancy increases the body’s water needs to provide a healthy environment for the baby to grow and develop. Dehydration during pregnancy can lead to several complications including:
- Neural tube defects
- Inadequate amniotic fluid
- Inadequate production of breast milk
- Premature labor
Such complications can result in birth defects or the need for nutritional support.
When can babies drink water?
Breast milk and infant formula are recommended from birth until 6 months. After 6 months of age, babies can consume small amounts of water in addition to breast milk or formula feedings.
Is drinking water before bed recommended?
The main downside of consuming too much water right before bed is the likely sleep interruption due to the need to use the restroom in the middle of the night, also known as nocturia. Such disturbances in the sleep cycle can lead to feeling less rested in the morning. (24)
It is clear that water promotes health when consumed in adequate amounts. A healthy human body is good at signaling the need for fluids and foods to maintain a hydrated state.
It is worthwhile to start your daily routine with a glass of water along with fruit and vegetables and make an effort to choose water over tempting caffeinated or alcoholic beverages.