Water is the most important element for your health. Human can’t live without water. There is common saying that “drink as much water as you can”.
But a new study finds that drinking too much of water can cause potentially fatal water intoxication. The new research challenges the popular idea that we should drink eight glasses of water a day for health.
This is for the first time, the mechanism that regulates fluid intake in the human body and stops us from over-drinking has been reported by the study team.
This is a multi-institute study led by Monash University has revealed for the first time the mechanism that regulates fluid intake in the human body and stops us from over-drinking, which can cause potentially fatal water intoxication. The study challenges the popular idea that we should drink eight glasses of water a day for health.
The study showed that a 'swallowing inhibition' is activated by the brain after excess liquid is consumed, helping maintain tightly calibrated volumes of water in the body.
Associate Professor Michael Farrell from the Monash Biomedicine Discovery Institute oversaw the work by University of Melbourne PhD student Pascal Saker as part of collaboration with several Melbourne institutes.
"If we just do what our body demands us to we'll probably get it right - just drink according to thirst rather than an elaborate schedule," Associate Professor Farrell said.
According to American paediatrician Aaron E. Caroll from Indiana University, there's absolutely no science to back this up, and there never was in another study about consumption of water.
"Contrary to many stories you may hear, there’s no real scientific proof that, for otherwise healthy people, drinking extra water has any health benefits,” he describes. "For instance, reviews have failed to find that there’s any evidence that drinking more water keeps skin hydrated and makes it look healthier or wrinkle free."
Then where did the great water myth come from? It's generally believed that the source is a 1945 Food and Nutrition Board Recommendation that declared, "A suitable allowance of water for adults is 2.5 litres daily in most instances.An ordinary standard for diverse persons is 1 millilitre for each calorie of food". As you might have guessed, 2.5 litres more or less works out to be around eight glasses. But what's usually ignored from that report is the crucial next sentence: "Most of this quantity is contained in prepared foods."
Actually, depending on your diet, there may be no reason to drink excess water at all. "Water is present in fruits and vegetables. It’s in juice, it’s in beer, it’s even in tea and coffee," writes Caroll. "Although I recommended water as the best beverage to consume, it’s certainly not your only source of hydration. You don’t have to consume all the water you need through drinks."
Before you object and tell us that coffee, tea, and alcohol dehydrate us, and therefore can't count towards our daily water intake, science has debunked that myth too.
In a 2002 review by physician Heinz Valtin from Dartmouth University in the US found that not only was there no peer-reviewed evidence to support the eight glasses a day rule, there was also no research to suggest that other drinks couldn't be used to adequately hydrate us.
Depending on the past study, the researchers asked participants to rate the amount of effort required to swallow water under two conditions; following exercise when they were thirsty and later after they were persuaded to drink an excess amount of water. The results showed a three-fold increase in effort after over-drinking.
"Here for the first time we found effort-full swallowing after drinking excess water which meant they were having to overcome some sort of resistance,"Associate Professor Farrell said.
"This was compatible with our notion that the swallowing reflex becomes inhibited once enough water has been drunk."
Dr.Farrell the Associate Professor, who works in the Monash University Department of Medical Imaging and Radiation Sciences, used functional magnetic resonance imaging (fMRI) to measure activity in various parts of the brain, focusing on the brief period just before swallowing.
One of the modern technologies of brain imaging the fMRI showed the right prefrontal areas of the brain were much more active when participants we retrying to swallow with much effort, suggesting the frontal cortex steps in to override the swallowing inhibition so drinking could occur according to the researchers instructions.
"There have been cases when athletes in marathons were told to load up with water and died, in certain circumstances, because they slavishly followed these recommendations and drank far in excess of need," he said.
Drinking too much water in the body puts it in danger of water intoxication or hyponatremia, when vital levels of sodium in the blood become abnormally low potentially causing symptoms ranging from lethargy and nausea to convulsions and coma.
Associate Professor Farrell said elderly people, however, often didn't drink enough and should watch their intake of fluids.
The study, 'Over drinking results in the emergence of swallowing inhibition: an fMRI study,' is published online in the “Proceedings of the National Academy of Sciences”. It was carried out in collaboration with the Florey Institute of Neuroscience and Mental Health,University of Melbourne and Baker IDI & Diabetes Heart Institute.
Certainly,it's worth noting here that the recommendations are for healthy people living pretty sedentary lifestyles in non-extreme temperatures. People living in hot climates, anyone who's exercising a lot or battling with an illness may very well need to drink eight glasses - or more - of water a day in order to alleviate their thirst.
Again,drink more water when you feel thirsty. But don't stress out about following some per-prescribed formula to health, because all it's going to do is see you running to the bathroom more often than you need to. And aren’t nobody got time for that.