According to a Penn State study, adults who sleep only six hours a day – unlike eight – can have a greater chance of being dehydrated.
These findings suggest that those who do not feel well after the night of bad sleep may want to consider dehydration – not simply a bad dream – as a cause and drinking more water.
The results of the study were published in the journal SLEEP November 5th.
The researchers looked at how sleep has affected the state of hydration and the risk of dehydration in adults in the US and China. In both populations, adults who slept for six hours had significantly more concentrated urine and 16 to 59 percent higher chances of being inadequately hydrated compared to adults who slept at night for eight hours.
The cause is related to the way the body's hormonal system regulates hydration.
A hormone called vasopressin is released to regulate the hydration status of the body. It is published throughout the day, as well as during bedtime hours, which the researchers focused on this study.
"Vasopressin is released faster and later in the sleep cycle," said Asher Rosinger, chief author and assistant professor of biological health in Penn State. "So, if you get older, you may miss that window where more hormones are released, which can lead to body hydration disorders."
Dehydration negatively affects many body systems and functions, including cognition, mood, physical performance, and others. Long-term or chronic dehydration can lead to more serious problems, such as a higher risk of urinary tract infections and kidney stones.
"If you get only six hours of sleep the night, it can affect your hydration status," Rosinger said. "This study shows that if you do not get enough sleep, and feel bad or tired the next day, drink extra water."
Two adult samples were analyzed through the National Health and Nutrition Survey, and one adult sample was analyzed through the Kailuan Chinese Study. More than 20,000 adults were included in all three samples. Participants were explored about their sleep habits, and also provided samples of urine analyzed by the researchers for biomarkers of hydration.
All data are obsessive both from cross-study or wavelength cross-sectional cohort studies; Therefore, the results of association should not be considered causative. Future studies should use the same methodology at different locations and examine this relationship in length over a week to understand the initial sleep and hydration status, Rosinger said.