If You're Sleeping 6 or Fewer Hours a Night, There's a Weird Health Effect We Didn't Expect

[Guest nicole]

We know that a good night's sleep is important for our health for all kinds of reasons, but there's a new benefit to add to the list: avoiding dehydration.

A new study suggests that anything under six hours of slumber a night could leave our bodies less than adequately hydrated.

Researchers found that people who slept six hours a night had significantly more concentrated urine and a 16-59 percent higher chance of being dehydrated, compared with adults who were getting a regular eight hours of shut-eye.

And according to the team behind the study, feeling less than 100 percent when you wake up after insufficient sleep might be down to dehydration too, not just the lack of shuteye – so an early morning glass of water could make a big difference.

The researchers think their findings could be traced back to the way the body's hormonal system regulates hydration; they focussed on a hormone called vasopressin, which the body releases during the day and the night to manage fluid levels.

"Vasopressin is released both more quickly and later on in the sleep cycle," says one of the team, Asher Rosinger from Pennsylvania State University.

"So, if you're waking up earlier, you might miss that window in which more of the hormone is released, causing a disruption in the body's hydration."

So, vasopressin does a crucial job of making sure our bodies don't lose too much water while we're sleeping – in fact, it can actually pull water back into the body from our urine.

If we're not staying asleep long enough for the right amount of vasopressin to be released, that can have a knock-on effect.

The study analysed records of more than 25,000 adults in China and the US, who were asked about their sleeping habits and had urine samples taken to look for biomarkers linked to hydration.

Vasopressin in particular wasn't measured, but indicators of it (like the levels of water in pee) were.

It's worth noting that the study isn't enough to prove a causal link – that less sleep causes dehydration – but it does suggest some kind of biological relationship between the two.

If You're Sleeping 6 or Fewer Hours a Night, There's a Weird Health Effect We Didn't Expect

https://www.sciencealert.com/six-hours-sleep-could-leave-you-dehydrated