It's the Content That Keeps Us Wide-Eyed

(Cleveland Clinic photo)

The blue light on our smartphone is a minor factor in keeping us awake at night. The content is a much greater disruptor.

If we come across alarming news, a scary movie or an annoying work email right before bed or in the middle of the night, the stress hormone cortisol can rise. A spike in cortisol provides an energy boost by moving glucose from a stored state in the body to an active state. “It’s like eating a candy bar,” says Jamie Zeitzer, co-director of the Stanford Center for Sleep and Circadian Sciences. Coming down from that energy rush can be difficult.

Positive content can be just as disruptive because it can increase the amount of dopamine or norepinephrine in the brain, two neurotransmitters Dr. Zeitzer says can excite the thalamus—the brain’s information-relay center—and disrupt the brain-wave oscillations needed for sleep.

Turning off the phone completely is an obvious solution. The sleep-tracking app is also effective; it dims the iPhone and Apple Watch 15 minutes before the targeted bedtime.

But if you must surf in bed, dear reader, I've been told this blog is an excellent soporific...