You might not be needing 8 glasses of water per day, says a new study published in Proceedings of the National Academy of Sciences.
The study focuses on human consumption of fluids. It is unique in its nature because it is the first revealing the regulatory mechanism that controls fluid intake. Conducted by a team led by researchers from Monash University, the findings oppose the common belief that we should drink 8 glasses of water daily.
The regulatory mechanism basically protects us from the harm of drinking too much. Over-drinking has been associated with problems like fatal water intoxication. Yes, you can actually die from drinking too much water (these are, of course, extreme cases). The volume of water within the body has to be kept within specified limits. Otherwise, if this balance is disrupted such that too much water is present in the human body, blood sodium concentrations will fall beyond a certain threshold, and the person might experience convulsions, and even fall into a coma; in less severe situations, he might have symptoms like lethargy and nausea. The human body is able to prevent any of that from happening through a “swallowing inhibition” mechanism (that restricts swallowing) which is triggered following the consumption of an excessive amount of fluids.
Lead researcher, Michael Farrell from the Monash Biomedicine Discovery Institute, explains that we can rely on this mechanism to know how much fluid to consume: according to him, we should just drink as dictated by thirst instead of following some other schedule.
The experiment involved rating the effort put in when swallowing water in two situations: when thirsty after exercise, and when convinced to consume excessive volumes of water. The findings show that the latter condition entails a much greater effort: the participants need to make three times more efforts 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,” says Farrell.
“This was compatible with our notion that the swallowing reflex becomes inhibited once enough water has been drunk.”
Another step taken by Farrell and his team was to measure brain activity prior to swallowing: the functional magnetic resonance imaging results display greater activity in the right prefrontal regions of the brain when participants would swallow with greater effort. This was interpreted as the frontal cortex overriding the swallowing inhibition to allow for the process of drinking. The authors mention how athletes have died because they were instructed to follow recommendations that dictated them to drink much more water than they needed.