The human body has apparently evolved some fairly ingenious mechanisms to keep itself from being disturbed during sleep. As you know, waking up during the night on account of thirst is not something that happens often. In fact, if people drink enough water before going to bed, this should almost never need to happen. In the instances when it does, it's because people haven't had enough to drink before sleeping. While awake, people can rarely go for 10 to 12 hours, maybe even more, without drinking water. But, during sleep, they have no problem doing so, Nature News reports.
According to a new investigation, it would now appear that the body's internal clock is directly responsible for this ability that we have. It has direct control over a water-storing hormone that regulates our need to intake or dispose of liquids. The direct mechanism that allows for this to happen was evidenced by neurophysiologists Eric Trudel and Charles Bourque, in a scientific paper they published in the latest issue of the respected scientific journal Nature Neuroscience. The two, who are based at the Research Institute of the McGill University Health Center, in Montreal, Canada, propose that the hormone vasopressin is directly responsible for storing water during the night,
They argue that the circadian rhythm, or the body's internal clock, allows for certain types of water-sensing cells in the body to activate other cells that produce vasopressin, when an individual is sleeping. They argue that the hormone essentially instructs the body to store water and not parade it around, as it does while the person is awake, and able to find water for drinking.
“We've known for years that there's a rhythm of vasopressin that gets high when you're sleeping. But no one knew how that occurred. And this group identified a very concrete physiological mechanism of how it occurs,” adds University of California in Los Angeles (UCLA) David Geffen School of Medicine neuroscientist Christopher Colwell. He has been studying the relationships between sleep and the circadian rhythm for many years. The new investigation was conducted on lab mice, but the results are very likely to hold out in humans as well. However, more research is needed before this correlation is validated.