New research suggests that insufficient sleep may lead to dehydration by disrupting the release of a hormone that plays a key role in regulating the body’s hydration levels.

 

Lack of sleep is already known to impair attention and judgment. Prolonged sleep deprivation has also been linked to a higher risk of conditions such as type 2 diabetes, high blood pressure, obesity, and respiratory disease.

 

More recent studies have also associated insufficient sleep with an increased risk of kidney disease and premature death. The kidneys play an essential role in maintaining hydration, and adequate water intake is important for supporting kidney health.

 

Despite these findings, relatively few studies have examined how sleep deprivation directly affects the body’s hydration status.

 

A new study led by Asher Rosinger, Ph.D., an assistant professor of biobehavioral health at Pennsylvania State University, aimed to address this gap. The research, published in the journal Sleep, analyzed hydration levels in adults from the United States and China.

 

The researchers examined data from two large studies: the National Health and Nutrition Examination Survey and the Chinese Kailuan Study.

 

In total, the team analyzed records from more than 20,000 healthy young adults who had provided urine samples and completed questionnaires about their sleeping habits.

 

The researchers assessed the urine samples for two indicators of dehydration: specific gravity and osmolality. They also used statistical models to analyze the relationship between sleep duration and hydration levels.

 

The results showed that people who regularly slept 6 hours or less per night had more concentrated urine than those who slept around 8 hours per night, indicating higher levels of dehydration.

 

According to the researchers, individuals who slept 6 hours or less were 16–59% more likely to be dehydrated compared with those who slept for about 8 hours. This pattern was observed in both the American and Chinese populations studied.

 

Interestingly, the researchers found no significant association between dehydration and sleeping 9 hours or more per night.

 

Commenting on the findings, Rosinger explained that people who consistently sleep only 6 hours per night may experience changes in their hydration status.

 

The researchers believe the hormone vasopressin may help explain this link. Vasopressin is an antidiuretic hormone that helps regulate the body’s water balance during both day and night.

 

Rosinger explained that vasopressin is typically released later in the sleep cycle. If someone wakes up earlier due to insufficient sleep, they may miss the period when higher levels of the hormone are normally produced, potentially disrupting the body’s hydration balance.

 

Although the study was observational and does not prove a direct cause-and-effect relationship, the findings suggest that sleep duration may influence hydration.

 

The researchers recommend that future studies investigate the relationship further, possibly through long-term studies that measure hydration levels before and after periods of reduced sleep.

 

Dehydration itself can have several negative effects on health. It may lead to symptoms such as muscle weakness, headaches, fatigue, mood changes, and impaired cognitive function.

 

For individuals who are not getting enough sleep, the researchers suggest paying extra attention to hydration, as drinking more water may help counter some of the effects of insufficient sleep.