One Clock Blog

Threat Vigilance, your Smartphone, and why you can’t sleep

Combat soldiers often have a tough time readjusting to life at home once the battle’s over. They’ve been trained to be on the alert for high-stakes hazards, in the form of incoming artillery fire or the sound of distant bomber planes approaching. They’re conditioned, in other words, for threat vigilance: a state of remaining alert to any and all possible dangers.

But when a soldier maintains a high level of threat vigilance upon returning from battle it can have a nasty effect on their general state of, well, relaxation. Because it’s telling them not to relax… constantly. 

Guess what else can provoke a similar level of threat vigilance? Your smartphone. 

While it may not explode in your face (fingers crossed), your smartphone is nevertheless the source of a lot of your most stressful triggers. From late-night emergency work emails to the ping of a notification from your child’s school, all these “threats” come from the same place: your phone. 

Now, no one is saying that keeping your smartphone in your bedroom at night is like sleeping in a war zone. But in a way… well, here’s how it works. 

Many of us use our phones as our alarm clocks. It’s simple and easy and it works. But when you bring your smartphone to bed with you, you’re also bringing that fiendish little source of stress into your bedroom, too. 

Even if you’re careful about not looking at your phone at bedtime, it’s probably sitting within arm’s reach of your pillow. And even if you don’t touch it at all, your subconscious knows it’s there. And if your subconscious knows it’s there, your vigilance level is heightened. 

Why? Because we’ve trained ourselves to pay attention to our smartphones, since they’re the most important source of emergency updates in our lives. It makes sense that we would stay alert – it’s in our best interest, in terms of basic survival. 

But staying alert is the opposite of what you want when you’re trying to get a good night’s sleep! As Harvard Medical School neuroscientist and assistant professor in the division of sleep medicine Orfeu M. Buxton explains, “This means that you’re never off, you’re always watchful, which is a hallmark of insomnia.” 

Threat vigilance is a key factor in the development of PTSD in soldiers. While using your smartphone as an alarm clock probably won’t give you PTSD, it’s almost certainly provoking a heightened state of anxiety in you at exactly the time of day when you’d rather be relaxed and calm. 

Humans have survived as a species for 300,000 years because our nervous systems are alert and sensitive to danger, protecting us from harm. But let’s face it: you’re probably not going to be attacked by a saber-toothed tiger anytime soon. In the 21st century we humans need to find ways to adapt our environment to our needs. Leaving your smartphone outside your bedroom is one really easy way to make your sleeptime sleepier. Because unlike an approaching infantry brigade, you really can put off that annoying email until tomorrow.