Intense cold can shock the body — but it might also be able to help you fall asleep and stay that way.
A new study from researchers at the University of Montreal and the University of Poitiers found that spending just five minutes in a frigid chamber cooled to a bone-chilling negative 130 degrees Fahrenheit might be the key to achieving deeper, more restful sleep.
In this cool experiment, 20 healthy young adults — nine women and 11 men, all averaging around 23 years old — stripped down to their underwear, socks, Croc-style shoes and mittens to brave cryostimulation sessions for five consecutive days.
The results? “Slow-wave sleep, considered the most restorative phase of sleep, increased by an average of 7.3 minutes during the first two sleep cycles [following cryotherapy],” Olivier Dupuy, an associate professor at UdeM’s School of Kinesiology and Physical Activity Sciences who served as a lead author on the study, said in a statement.
But it’s not a one-and-done deal. The study, published in the December issue of the journal Cryobiology, found that just one frosty session wasn’t enough to improve sleep, with benefits only appearing after five back-to-back chills.
Researchers also identified a marked gender difference, with women seeming to enjoy a greater advantage from the icy than men.
While the study involved participants without sleep issues, researchers said cryostimulation could be particularly helpful for those struggling to get enough shut-eye.
In 2020, the latest year for which federal data is available, 14.5% of U.S. adults had difficulty falling asleep most days or every day in the previous month, and 17.8% of adults had trouble staying asleep, according to the Centers for Disease Control and Prevention.
An added bonus: Extreme cold might help your mood, too. Repeated cryotherapy sessions had a positive effect on participants’ psychological wellness, reducing their anxiety and improving their overall mood, with women reaping more of those benefits as well.
There’s also an upside for sports stars.
“For elite athletes, it could help with recovery, while for the general population, it could help people with chronic inflammation or mild dementia when used in combination with physical exercise,” said Dupuy.
The study was part of a larger effort to understand cryostimulation’s effect on the body, which began earlier this year when Dupuy and his colleagues received funding to study its use in athletes preparing for the 2024 Paris Olympics.
Other research has shown time spent in the chilly chamber can help alleviate muscle and joint pain, boost the immune system and increase energy levels. For skin care buffs, the treatment has even been shown to stimulate collagen production.
There are still many lingering questions about how cryostimulation could help other ailments, but Dupuy said one thing is clear: “This is not a placebo effect.”
