It's almost common knowledge that you need to drink 8 glasses of water a day, but is drinking so much water really good for us? A study suggests that drinking too much water activates a mechanism in the brain that inhibits swallowing. Once this inhibitory mechanism is surpassed, we face the risk of water intoxication, which is medically known as "hyponatremia." Hyponatremia is a condition caused by an excess of water in the body, leading to dangerously low sodium levels in the blood. It can cause drowsiness, nausea, seizures, and even coma, and if left untreated, it can lead to death within a few hours.
It's healthier to drink water when you feel thirsty
Dr. Michael Farrell, the lead researcher from Monash University in Melbourne, said, "The correct way to drink water is according to your body's needs. It's healthier to drink when you feel thirsty than to follow a precise drinking schedule. We found that after drinking excessive amounts of water, swallowing becomes an effort, meaning we have to overcome some resistance. Marathon athletes have died in certain situations from drinking too much water because they blindly followed advice to drink large quantities, ultimately consuming far more than their bodies needed."
Functional magnetic resonance imaging (fMRI) was used to measure activity in different parts of the brain, primarily reflecting the brain's instantaneous reaction before swallowing. Researchers had participants drink water under two conditions after exercise: one when they were very thirsty, and the other when they were asked to drink excessive amounts of water. The results showed that the brain's swallowing mechanism's workload increased threefold after over-drinking. However, the scans showed that the prefrontal cortex of the brain was more active than usual when participants drank excessive amounts of water. Researchers believe that people can only drink water when the prefrontal cortex intervenes to overcome the swallowing mechanism. Dr. Farrell noted that it's important to be aware that older people often do not consume enough water and should be monitored for their fluid intake.
If water enters the body faster than it is expelled, the electrolytes in the blood become diluted. This allows water to move from the blood into cells and organs like the brain, affecting their function.