All higher animals need water. Scientists say, it is because all land animals have evolved from primitive sea animals. So, we swim in watery fluids when we are in the mother’s womb. Even after birth and into adulthood, the human body functions properly only when it has 60-70% water. After air, water is the most important substance humans need for sustaining their life.
This dependence on water for our survival as well as proper functioning of our bodies gives rise to many notions – if not outright myths – some that promote wrong usage of water.
Common beliefs about optimum quantity of water intake
Let us examine some common notions about how and how much water we should take.
- Drink at least 8 glasses or 2-3 litres of water a day.
You don’t need to follow such a rapacious water regimen.
Studies have found that adult females need about 2 litre of water a day and males about 2.5 litre. About 80% of that comes from fluids and 20% from food. Those who do not take enough fluids such as tea/ coffee, hydrogenated/ sports drinks or juices may need to take some cups of water – depending upon many factors discussed later.
Except for some exceptional situations (e.g. very young age, severe sickness, severe mental health issues, sudden heat), we can safely go by the signal our body gives us for drinking water, in the form of thirst. Some additional water helps, if taken in the right manner.
Excess water can lead to hyponatremia or sub-optimal mineral concentration in body fluids, leading to swelling of tissues. For this reason, too much water, that too in one go, is not recommended even when one is very thirsty. Since kidneys cannot flush out more than a litre of water in an hour, consuming fluids more than that is not at all recommended. A few cases have occurred in which athletes have died due to excess water intake.
In some health situations, e.g. kidney diseases, water intake has to be regulated. Such diseases can get aggravated with excess drinking of water. Certain medicines (e.g. NSAIDS drugs for inflammation) cause retention of water in tissues.
- Drinking a lot of water removes toxins, keeps kidneys healthy.
It is a fact that water is essential for removal of metabolic residues and byproducts, and toxins. But for that, you do not need to take more water than required. Studies have found no remarkable health improvement with additional intake of water. Additional water intake, in fact, puts additional burden on the kidneys, though temporarily.
Studies have shown that good amount of urine formation reduces the risk of kidney stones. But stone-formation in kidneys depends on many other factors.
- When your urine is yellowish, it indicates dehydration, and you must increase water intake.
Urine has a natural yellowish colour, which is perfectly normal. Only if the urine is more yellow than normal does it indicate that the body needs more water. In some conditions, even that may be fine. For example, some medicines and foods give the urine an extra yellow colour.
However, when the urine colour is darker than normal and you have not taken enough fluids for some time, it is high time you take a glass of water.
- Drinking lots of water keeps skin moist and improves complexion
Adequate amount of water is definitely good for body parts, including the skin. However, taking additional water does not make skin any more moist or soft or glowing.
- Taking more water leads to reduction in weight.
In some studies, it has been found that taking extra water leads to reduction in weight, perhaps because water does not add to energy intake but energy is spent in disposing off the extra water.
Taking more water before meals leads to less appetite, which may result in less food intake and in turn less gain in weight. But that upsets some people’s digestion.
However, water does not directly lead to burning of calories or reducing the deposition of fat in the body.
- Drinking 4-5 glasses of water first thing in the morning is a proven ‘Japanese water therapy’. It treats diseases from constipation to cancer, depending on the days for which the water is taken.
Taking water in the morning is considered good, but taking that much water is not found to be of any great therapeutic value as claimed on many websites and videos.
In fact, some people may feel pain or discomfort, and even develop minor ailments by taking that much water in one go.
In the so-called Japanese water therapy, one should not take any food for the next 45 minutes. That makes sense; one should avoid taking food immediately after drinking water, and if more than two cups of water is taken in one go, enough time is needed for it to go down the stomach.
- Drinking cold water leads to solidification of fat. So, this causes fat deposit in blood vessels.
Drinking too cold water is not advisable, and it does temporarily slows down the digestion. However, the temperature of water is not linked to fat deposit in blood vessels or the heart.
- If you keep drinking water throughout the day, that boosts immunity and cures many common health issues such as kidney stones, flu, headaches and depression.
Drinking water in small amounts once in a few hours is a good practice if that suits your body and does not lead to fullness of stomach or discomfort.
Taking some extra water is also useful if you are not taking enough water through food and other drinks.
However, drinking water at regular intervals through the day does not cure diseases as claimed by ‘water therapies’ being touted on the web by people with no knowledge or expertise on health matters.
- You should take a glass of water before sleeping so that you remain hydrated throughout the night.
In our normal routine, we spend the night sleeping. That should not require much water intake, unless one does not take fluids for many hours during the day, eats a very solid dinner, or the night is hot and humid – leading to a lot of sweating.
- Feeling thirsty is too late. By that time you are dehydrated.
Usually the reverse is true. Feeling thirsty is the sign that you should drink water. Even if you are not able to drink water after feeling slightly thirsty, no big harm is done. Once water in the body starts becoming less than that is required by it, brain sends signal to the kidneys to conserve water; that’s why, the urine gets concentrated and looks yellow.
What is the right quantity of water one should drink in a day?
This is one of the simplest questions I have dealt with in this column, but it does not have a simple answer. 😉
The discussion above shows that there cannot be a one-word answer to this question. Body’s water requirement depends on many factors including age, health status, weather, food habits and type of food intake, and medicine being taken, and so on.
Each person’s body make-up is unique and so is its water need. You might have seen some people who do not seem to be drinking water at all and some who keep taking water all the time. People who do not drink much water could be taking 5-6 cups of tea or lots of carbonated drinks in a day.
As long as you are healthy and act according to the signals of your body, you seldom need to force or remind yourself to take water. You can take some additional water just to ensure that you remain hydrated enough.
It has been found that minor dehydration can lead to temporary symptoms (e.g. lack of concentration, fatigue, reduced strength) and these go away once enough water is taken in. However, a major loss of water from the body can be dangerous.
What are the circumstances that can lead to dehydration?
The following are common situations in which either water intake is less than required or the body loses more water than normal, or the body is unable to tell about the need to hydrate. Consider these:
- Urine is the most obvious way of losing body water. In some situations such as constant cold weather or taking diuretic foods or medicines, one can lose more water than normal.
- A lot of water can be lost due to perspiration. This happens when one is in hot weather (even if the perspiration is not apparent), suffering from fever or under some medication. Physical activity, including strenuous exercises and marathon races, require additional water intake.
- Breast-feeding and pregnancy may need some additional fluid intake.
- Some diseases (e.g. diarrhoea) can lead to heavy water loss. In such cases, not only regular drinking of water in small doses but also with some electrolytes is recommended so that water is efficiently absorbed by the body.
- There also are serious health conditions in which the patient is not able to feel or express the need for water.
- When one perspires a lot or is engaged in physical activity, there can be times when the loss of water is not immediately compensated by drinking water. When one is under the sun in hot weather, this can lead to severe dehydration.
- Even common foods/ drinks have chemicals that disturb the water balance in blood and tissues (e.g. caffeine beverages, alcoholic drinks, energy drinks, canned juices, drinks with too much sodium or sugar).
Keep taking enough fluids and keep well-hydrated. Do not drink water in excess in the hope that it would miraculously cure chronic diseases.
- How Much Water Should You Drink Per Day?
- Water, hydration, and health
- Water intake and Kidney Stones
- Japanese Water Therapy: Benefits, Risks, and Effectiveness
Disclaimer: The information and advice given here are of general nature, and should not be treated as medical advice. For your specific water needs, especially if you pass through any of the ‘special circumstances’ mentioned above, do consult a doctor.
*About the author: This article has been contributed by MK. He does not like to call himself a rationalist but insists on scrutiny of apparent myths as well as what are supposed to be immutable scientific facts. Please don’t take the views of the author as the views of Raag Delhi.