A study led by Monash University researchers reveals that we do not need to drink eight glasses of water a day. The researchers explain that our body stops us from overdrinking, which can be deadly, so we should only drink water if our body demands us to instead of following a fixed schedule.

The multi-institute study published in the Proceedings of the National Academy of Sciences shows that our brain activates the swallowing inhibition function after we drink too much liquid. This mechanism helps regulate water intake and maintain the volume of water in our bodies.

The study involved asking the participants to rate the amount of effort they exert to swallow water if they are thirsty after exercising and when they were told to drink excess amount of water.

“Here, for the first time, we found effort-full swallowing after drinking excess water, which meant they had to overcome some sort of resistance,” says Michael Farrell, an associate professor from the Monash Biomedicine Discovery Institute. “This was compatible with our notion that the swallowing reflex becomes inhibited once enough water has been drunk.”

This has been confirmed using fMRI. Brain scanning results reveal that the participants’ prefrontal areas become more active when they have to drink water with effort. This indicates that the frontal cortex is used to override the swallowing inhibition.

The research team asserts that drinking too much water leads to water intoxication or hyponatremia, or abnormally low sodium levels. Symptoms of the condition include lethargy, nausea, convulsions and coma.

The researchers cite athletes in marathons that overdrank water and died. They recommend that we must watch our intake of fluids and we should only drink if our bodies say so.

Collaborators of the study include researchers from the University of Melbourne, the Florey Institute of Neuroscience and Mental Health and the Baker IDI & Diabetes Heart Institute.