All this while, we have been made to believe that we need 8 glasses /2L of water daily. But, like we know that requirement for food differs from person to person, in the same way fluid requirements should also be individualized and not same for all? It is still a controversial debate but we present some science for you to rationalize and make your own decision.
Water balance: Gain and loss
Water lot each day
About 700ml water is lost each day through skin and breath. Another 100ml is lost through faeces/ stools and about 1.5 L as urine and about 200ml in normal perspiration. This totals upto 2.5 L of water lost in a day
These losses may increase or decrease depending upon:
- Physical activity – Exercise increases body temperature causing sweating and leads to water loss.
- Illness – In case of diarrhoea or vomiting , body water may be lost
- Old age- We can assume that with age our natural reflexes may also slow down and hence keeping an elderly well hydrated may require conscious efforts
Our body’s metabolic processes produce 250ml and 750ml comes from food, so another 1.5 L needs to be replenished by fluids which is only about 6 glasses.
All beverages usually have substantial amounts of water such as juices, tea, coffee, coconut water, etc. so these may also fulfill part of the requirement
So how much allowance is left for pure water?? Definitely not 8 glasses! Overloading water can have serious consequences and is termed as water intoxication.
What happens when excess water is consumed?
- Early signs of overhydration include confusion, disorientation, nausea, and vomiting
- Prolonged state may lead to compromised mental abilities and some psychotic symptoms as the water enters brain cells
- Excess water in the body leads to dilution of the solutes such as sodium leading to hyponatremia. Severe hyponatraemia can lead to seizures, coma, and death
Natural mechanisms for regulating water intake
Thirst- Thirst is by far the most effective mechanism for regulating water intake. As and when your body needs water, the brain signals it in the form of thirst. If we try to override thirst for some reason then it definitely spells trouble
Color of urine– Urine colour is also great marker of hydration. If it is colourless or pale yellow , then you are well hydrated. A darker urine often indicates poor hydration
Impaired swallowing– Recent research has also shown that once water requirements have been fulfilled, swallowing water becomes difficult. It is body’s natural mechanism for telling us that we do not need more water. Effort-ful swallowing has been observed in test subjects when they were asked to drink excess water whereas when we are actually thirsty swallowing water is effortless.
The best way to avoid dehydration or overhydration is to drink water whenever your body asks for it. Some individuals are in the habit of suppressing the need to drink water because they may be too busy at work or traveling and not wanting to use washrooms outside. Over time, body may becomes accustomed to this conscious avoidance. But, we must know that drinking enough fluids is important to keep cells hydrated and functioning well so thirst or dehydration signals cannot be taken casually. At the same time, there are some health enthusiasts who consciously drink lots of water in an attempt to stay fit.
Remember , moderation is the key even when it comes to water!
Dr Pooja Chhawcharia is the Senior Nutritionist at eKincare with over 7 years of experience in Nutrition education, diet counseling and research. She is a Registered Dietician with the Indian Dietetic Association and Certified Diabetes Educator recognized by the International Diabetes federation . She is also interested in ancillary sciences such as Yoga and Naturopathy.