A new study that's challenging the popular idea that we should drink eight glasses of water a day for health purposes shows that a 'swallowing inhibition' is activated by the brain after excess liquid is consumed. This inhibition mechanism helps maintain tightly calibrated volumes of water in the body.
The lead scientist has pointed out that if we just do what our body demands us to, we'll probably get it right. In other words, it is the best practice to just drink according to thirst rather than an elaborate schedule.
Building on a previous 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, demonstrating resistance to over-drinking.
In accordance to this, fMRI showed the right prefrontal areas of the brain were much more active when participants were trying 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.
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.
