Why and how much should one drink water?
‘World cannot exist without water’ said Thiruvalluvar. Water is one of the fundamental needs of all organisms, from plants, microorganisms to human beings. It is also essential for our well being. It is amazing to understand how our life and its functioning for continuity depend essentially on the elements of water.
What is the need for drinking water all through the day and how it is excreted primarily through sweat and urine and also by various ways from the body as waste after being absorbed in? Have we every seriously thought about it or forget about its essentiality the moment after satiating thirst with one or two glasses of water?
Water cannot be ignored with such callosity. Can you believe the fact that our body is filled almost 50-70% with water in terms of body weight? Dr. P Krishnamurthy, General Physician from Tanjore, describes the essentiality of water in our daily life.
Water content … 60% for men, 55% for women!
For the cellular functioning of the body water and electrolytes are the key factors. They are generated and completely absorbed in the intestinal tract. Through extracellular gaps among the cells, water gets through the cells by osmoregulation. Of the water content in the body about 2/3 of it is contained within the cellular matrix for various metabolic functions and that is the reason it is inevitably needed by the organs both internal and external. The content of the water will vary depending on the amount of fat accumulation in the tissues.
Of the total body weight, men have 60% of water in it and 52-55% for women. Clinical reports observed that for obese and aged men and women its content will considerably come down.
A person with an average body weight of 68 kg could hold about 41 liters of water, of which 23-27 liters will be available within the tissues and only 7 liters will be seen external to tissues and their surroundings with. Medical research reveals that about 4 liters will be found in the plasma of circulatory systems in the body and remaining amount is being used for the metabolic process in the body.
But for a newborn baby, almost 85% of water is contained in its body and it will gradually come down to 75% during childhood and will further down as it grows up. ‘Severe lack of water in the body will lead to fainting, unconsciousness and it could even be fatal’ informs the book ‘Food and Wellbeing’ written by Dr. Mohan, Urologist from Tanjore.
Daily 2.5 liters of water!
It is important to know how much one should drink water, an inevitable molecule, in a day. At least 2.5 liters water should be taken daily. Its need will increase depending upon loss of water in the body during summer, after physical exercise, or during sickness such as dysentery, vomiting etc.
In general, we drink water only when we are thirsty. But that is not sufficient. Our body takes in water from other sources such as liquid foods and drinks and also from metabolic processes taking place in the body. It’s interesting to note that our body made of numerous cells and the water molecules required for their functioning are stored outside the cells. The stored water is utilized by the cells when needed and also during emergency conditions when the body is dehydrated due to lack or loss of water. Body prudently handles any situation of lack of water in the body in such a way by striking a balance between the amount of water excreted from the body and the amount retained within the body. That is the ingenuity of the biological intelligence of the body in handling water crisis within it.
A key point one should know in regard to utilization of water in the body is that body generates its own water other than what we take in. If we drink 1500 mL of water in a day it’s not that body uses only with that amount of water for various bodily functions. Biologically, it secretes its own water in different forms to carry out its routine metabolism.
For example, water utilized in various amounts in the organs, especially in the gastro-intestinal tract; 1500 ml in saliva, 2000 ml in a stomach, 500 ml in a bile duct, 1500 ml in spleen and 1500 ml in the small intestine. At the same time, it gets reabsorbed from other parts such as 1400 ml from a colon, 6700 ml through the portal vein. Of the total volume of 8200 gastrointestinal tracts of water richly available in the gastro-intestinal tract 8100 ml is reabsorbed by the specific part of the track and only 100 ml is being excreted from feces. Such is the precision of water conservation in the body, reveals a book on physiology by Davidson.
Secretion, digestion, transport, absorption, cleaning!
Absorption, Distribution, Metabolism and Excretion (ADME)
A transformation from water to urine is not a mere transport process. There are vital processes that happen during its journey, entering orally, being absorbed by internal organs for their specific and unique biological functions, especially the gastrointestinal tract where metabolism takes place primarily, after completing absorptions of major and essential products for the body to survive and eliminate unwanted materials and excreted out of the body through urine, faeces, and sweat pores and also through saliva. Scientifically it is termed as ADME. Besides, water facilitates smooth movements of joints, preventing friction and eventual damage to bones. It also helps in clearing out excess salts in the body avoiding renal stones and calculi and excess acidity in the body that leads to gastritis. Above all, water helps in maintaining body temperature, especially the warm-blooded (homeotherms) animals including human beings, keeping homeostasis of body temperature against the ambient environmental temperature.
In order to understand how water is utilized in the body, it is better to quantify what is excreted. About 1500 ml by urine, 100 ml by feces, 200 ml by sweat is excreted from the body. Besides, during breathing where oxygen is taken in and carbon dioxide is vented out, about 700 ml of water also gets out of the body during respiration.
In this era of increased scientific advancement, it is possible for human beings to create anything artificial through technological sophistication leading to breakthrough innovations and inventions. However, it is not at all possible to create water artificially or synthetically. It is one of the nature mandates that all organisms, from microbes, plants, birds and animals, including human beings, must depend on water for them to survive. No software can modify that mandate. That is why we are continuously reminded and sensitized by environmentalists and government agencies that water is precious and it needs to be conserved at any cost.
But water politics is one of the worst and ugliest cures that humankind faces today and it is exacerbated by water pollution, inequity in distribution, and above all depletion of fresh water due to over-exploitation and also through climate changes. But whenever humankind goes against nature water tries to reconcile our bondage with it.
Further, it is also important not to drink water in excess. Anything in excess will lead to complications and it is applicable to water intake too. Kidneys may find it overwhelming to deal excess of water in the body. If there is a lack of water in the body the central nervous system gets activated that in turn prompts a feeling of thirst within us and it is satiated only by drinking water immediately. In general, the body has its own resilience, the ability to balance itself during the crisis and therefore we can avoid anything in excess.
We can live up to fifty days without food. But without water one cannot survive more than a few days. There is a close affinity between water and minerals such as sodium and potassium. Increased sodium level in the body will lead to thirst. And if it is decreased kidneys will excrete an excess of water from the body leading to dehydration. In order to stop water loss, a hormone called vasopressin is secreted from the brain that prevents water loss through renal function. This, in turn, affects the vital functions of heart and kidneys. More bodily water accumulation affects lungs and its internal air flowing devices called alveolar air sacs, leading to breathing problems and suffocations. This condition needs immediate medical care.
Whatever the physical conditions, if one feels dry mouth, feeling weak and exhausted, it is advised to immediately take ORS (oral rehydration solution), i.e., salt-sugar mixed fluid, buttermilk, tender coconut, fresh fruit juices. Water treatment is one of the alternatives in natural medicine. In the case of emergency, it is better to get admitted to a hospital and get IV (intravenous) saline fluids immediately.
Women should not avoid required water!
A decrease of 5% body fluids will lead to 30% reduction in productivity. That is the vitality of water in our body. This is a fact that should be remembered by us, women in particular. Most of the time, women do not drink adequate water during travel in order to avoid frequent urination. They should be aware of the health complications of avoiding water intake.
Due to inadequate toilets available during a long journey and also for safety concerns women force themselves taking less water and also avoid urination even if it is a nature call. This will lead to dehydration and prolonged retention of urine leads to urinary tract infection. During the menstrual cycle, only 40-50 mL of water is lost along with blood. So it is not a big concern. But if there is prolonged menstrual cycle or it is a menopause process going on, there will be more sweating due to hormonal imbalance leading to a lack of water in the body. Therefore women should take these factors seriously and make alternative arrangements accordingly, not risking their own well-being at any cost.
During old age, cellular functions will decline. The body may need water but there won’t be thirst. Aged persons may show disinterest in taking water due to inability, or frustrations, sorrows or disgust. But it is more than needed for them to take adequate water whatever their conditions are, be it physical or psychological. The biologically essential functions through water will continue relentlessly in all organisms. If it is disturbed due to various reasons there will be health-related implications.
Also, daily intake can be adjusted based on the body weight, age, seasonal changes, and extent of physical exercise and special water requirements in case of specific illness especially related to renal functions.
Avoid using water sold in bottles, packets, cans unless their quality is assured or validated. Similarly, it is better to avoid bottled cool drinks where there is an excess of synthetic compounds and preservatives. Dysentery, cholera, typhoid and other viral infections could affect us due to poor quality or contaminated water. Therefore it is advised to drink filtered and boiled water considering increased pollutants and contaminants in water sources. Pure water in any container, even if it is in mud pot is always better than those sold commercially with poor or no quality check.
Prevention is better than cure and it adds to our experience if we happen to deal with it successfully. Let us realize the preciousness of water in our daily life and be prudent in using it, protecting it for us as well as for the future generation.
(This article originally written in Tamil by Akila Krishnamurthy in vikatan.com is now reproduced in English by Amalan Stanley)