A new study says that drinking too much activates a protective swallowing inhibition in the brain. And can cause people to suffer from water intoxication.
It’s a common piece of advice – drink six to eight glasses of water, or fluid, every day. The suggestion has been around for some time and appears on the NHS website.
But while drinking plenty of water to stay hydrated is important, experts are warning that consuming too much might actually been damaging to our health.
The danger is down to sodium levels in the blood. Too much water can lead to hyponatremia, which is when vital levels of sodium in your bloodstream become abnormally low.
Hyponatremia can lead to lethargy, nausea, convulsions and, in the worst instances, may even lead to a coma, or even death.
“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.
“This was compatible with our notion that the swallowing reflex becomes inhibited once enough water has been drunk.
“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.”
For the study, Dr Farrell and his colleagues asked people to rate the amount of effort needed to swallow water under two different conditions.
Participants drank immediately after exercising – when they were thirsty – and then later in the day when they didn’t feel as if they needed a drink.
Imaging software was used to measure activity in the brain thereafter.
People showed signs of considerable effort when drinking seemingly unnecessarily, and scans showed the brain was affected more then too.
It’s then that the brain tells us to override the desire to have a drink – and when “swallowing inhibition can occur.”
And it’s then when salt levels can be impacted, and hazards might come about.
Despite this, Dr Farrell stressed that staying hydrated and drinking plenty of water every day is important. But you might not want to force liquid down.
The study was published in the Proceedings of the National Academy of Sciences.
Researcher Dr Michael Farrell, from Monash University in Melbourne and who worked on the research, said: “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.