It is perfectly natural to feel confused after a night of throwing and turning or staying too late. But new research suggests that there may be more than just sleep deprivation: It can also dehydrate, researchers say, and drink more water can help you feel better.
The study, published this week in the magazine Sleep, found that people who reported sleeping regularly at six hours a night were 16 to 59% more likely to be "poorly hydrated" (based on their urine samples) than those who said they were normally sleeping eight. Both the United States and Chinese adults participated in the survey – about 25,000 people in all – and the results were consistent across both populations.
This does not mean that people who sleep less also consume less. in fact, the authors of the study actually check for the total fluid consumption among some of the participants. They found that even when people reported eating the same amount, those who slept less were more likely to have more concentrated urine and other signs of dehydration.
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So what's going on? The authors of the study say that it probably has to do with a hormone called vasopressin, which helps regulate the body's hydration status.
Vasopresin is released both day and night, but production begins much later in the sleep cycle, lead author Asher Rosinger, assistant professor of biomedical behavior and anthropology at Penn State University, said in a press release. "So if you wake up earlier, you might lose the window to release more of the hormone, causing a disruption in body hydration," he added.
The authors point out that poor sleep has been associated with previous studies with chronic kidney disease and say that dehydration can be a major driver of this relationship. Long-term dehydration can also increase a person's risk of kidney stones and urinary tract infections.
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Because the study was based on self-reported sleep data and only looked at the effects of urine at a time, it was only able to find a relationship between the two – not a cause-and-effect relationship. Future studies should consider this relationship over a week, the authors wrote in their paper to understand how people's hydration and sleeping conditions change every day.
The National Sleep Foundation suggests that adults should take seven to nine hours of sleep per night and that it is best to keep the time to sleep and the wake-up time as consistent as possible. (In this study, sleeping more than nine hours at night does not seem to have any effect, in any direction, on the hydration status.)
Of course, you do not really need it else The reason why sleep skimping is bad for you is also associated with a higher risk of developing cardiovascular disease, over-consumption of food, weight gain (even when not associated with over-consumption) and diabetes, to name a few. It can also cause short-term problems such as irritability, difficulty in concentrating, memory problems and drifting.
But dehydration itself has been shown to cause headaches and fatigue and affect mood, knowledge and physical performance – which may add the already negative effects of a sleepless night, the authors say. "This study suggests that if you do not have enough sleep and feel bad or tired the next day, drink extra water," Rosinger said.
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