Since middle-school health class, you’ve been told to drink eight glasses of water per day for better wellness. But many people find this hard to swallow — literally. Now, a new study may tell us why. Researchers have identified a brain mechanism that stops us from swallowing too much liquid when we are not thirsty.
Being hydrated is important. To work correctly all the cells and organs in your body need water. It lubricates the inside of your mouth and throat, cushions joints, protects the spinal cord, regulates body temperature, and helps food through intestines. Water also dissolves minerals and nutrients so that they are more accessible to the body, and transports waste out the back door. In fact, 60-70 percent of our body is made up of water.
Water leaves your body through activities like sweating, urination, and even breathing. Drinking plain old water is the best source of fluid, because it doesn’t contain calories, caffeine, or alcohol, but you can also gain water through foods and other drinks. The recommended amount of water to be consumed per day varies from person to person, depending on their size, how active they are, and how much they sweat. The idea of drinking eight 8-ounce glasses of water per day, (which works out at around 1.9 liters) is an easy-to-remember amount that puts people on the right track. But is it right for you?
A new study that suggests we should drink only when we are thirsty, because swallowing when we aren’t thirsty is physically challenging. Researchers at the Biomedicine Discovery Institute at Monash University in Australia published their finding in the Proceedings of the National Academy of Sciences. They discovered a mechanism in the brain that makes swallowing excess water difficult.
The team enrolled a number of participants and asked them to drink large amounts of water immediately after exercise when they were thirsty, and later on in the day when they were not thirsty. They asked the participants to rate how difficult it was to swallow. Compared with water consumption just after exercise, participants found it three times more difficult to drink water when they were not thirsty. They were having to overcome some sort of resistance, according to the research.
The team measured brain activity just before each episode of drinking. They discovered that certain areas of the right prefrontal cortex of the brain showed significantly higher activity when participants had to make an effort to swallow the water, suggesting that this brain region “overrides” the swallowing inhibition to allow excess water consumption. The brain likely works this way because drinking too much water can cause as much or more harm to your body as not drinking enough.
When it comes to water intake, we may do best by listening to our body’s needs. To get it right, just drink according to thirst rather than an elaborate schedule, researchers recommend. Still, the team points out that water intake remains essential to human health, and there are certain groups — such as elderly individuals — who tend not to consume enough water and should make an effort to drink more.