The United Kingdom’s vote last month to leave the European Union set wheels in motion across the globe. British Prime Minister David Cameron announced plans to resign. Stocks slumped. The British pound nosedived. And politicians across the U.K. (and the U.S.) went at it.
But the so-called Brexit referendum had another effect on people in the U.K.: Some lost sleep.
More specifically, London residents who use Jawbone UP activity trackers slept on average 35 fewer minutes on the night of the Brexit vote than they had averaged the rest of the year, according to aggregated, anonymized data from Jawbone. Sleep data was not available for people in the rest of the U.K.
Dubliners slept 15 fewer minutes than usual.
Phyllis Zee, director of the Sleep Disorders Center at Northwestern Memorial Hospital, said the data is an interesting way to look at large-scale sleep trends.
Previous research has revealed major traumatic events like hurricanes, earthquakes and terrorist attacks disturb sleep patterns. And data like Jawbone's can help illustrate how the news cycle -- particularly when it's stressful or uncertain -- can affect our sleep, Zee told The Huffington Post.
But the Jawbone UP data shouldn't necessarily be taken at face value, she explained.
A big caveat is that the activity tracker uses movement to assess whether someone is asleep or awake, which is an indirect measure, Zee said.
Such data can paint a picture of sleep trends and how long people are resting. But the trackers are not as accurate as measuring sleep in a lab, where doctors can monitor brain activity and sleep stages, LiveScience previously reported.
“You move the same amount whether you’re in deep sleep or lighter stages of sleep," Hawley Montgomery-Downs, a sleep researcher at West Virginia University, told LiveScience.
Another important caveat to keep in mind is that because the Jawbone data only includes people who chose to buy and wear a Jawbone UP device -- a sample that includes "tens of thousands" of people, the company said -- it doesn't necessarily provide a representative sample of Londoners or Dubliners.
Brexit Uncertainty A Recipe For Anxiety
That said, current events can affect an individual's sleep for a variety of reasons.
For one thing, not knowing how something is going to affect you individually is a recipe for producing more nervousness and anxiety, which puts us in a state of hyperarousal, Zee said.
“You can’t shut the brain down," she said. "You keep thinking and reverberating these thoughts.”
Anxiety also makes it harder for you to fall asleep or sleep deeply, she said.
“Your heart rate is higher; your blood pressure tends to be higher," Zee explained. "It’s a physiological and biological arousal and a mental arousal.”
This type of reaction can affect anyone to varying degrees, she said -- particularly people who are prone to being more anxious or having trouble sleeping.
“You can’t shut the brain down. You keep thinking and reverberating these thoughts.”
And there’s the straightforward reason that breaking news may lead us to stay up later than usual to watch and read reports of what’s going on.
“The news media is continuous," Zee said. "Every channel you flip to, they're talking about it -- and about the ramifications.”
'You Want To Try To Nip It In The Bud.'
The good news is that 35 minutes of sleep loss in one day will probably not have a significant impact on somebody’s health, Zee said -- although she noted that losing 35 minutes of sleep every day can certainly become a problem over time.
A few sleepless nights are more concerning if you're prone to sleep trouble or insomnia.
Insomnia often occurs when someone begins a cycle of sleeplessness following a difficult or stressful time, Philip Gehrman, assistant professor of psychology in the Behavioral Sleep Medicine Program at University of Pennsylvania’s Perelman School of Medicine, previously told HuffPost.
"[Our] bodies get stuck in this cycle of not sleeping well -- which can last for decades if left untreated," he said.
“[Our] bodies get stuck in this cycle of not sleeping well -- which can last for decades if left untreated.”
Good sleep hygiene is key to keeping a bout of sleeplessness from turning into something that lasts longer, Zee said. Practice relaxation and meditation techniques before bedtime. Exercise during the day, but not too close to going to sleep. Clock some time in the sun during the day and avoid bright light later at night. And be sure to actually go to bed on time, Zee said.
And consider seeing your doctor if you struggle with sleep for about two weeks, she suggested.
"It depends on how severe and how close [the stressor] is," Zee said. "But you want to try to nip it at the bud to prevent it from becoming chronic."
Sarah DiGiulio is The Huffington Post’s sleep reporter. You can contact her at sarah.digiulio@.