- Body temperature falls (though hands and feet warm up).
- Circadian clocks synchronize.
- Melatonin (the hormone that sets our sleep/wake cycles) flows through the body.
- The brain quiets.
- Blood pressure falls.
- Pulse rate slows.
- Breathing evens out.
- We now sleep an hour and a half LESS than we did on work nights half a century ago. It used to be eight and a half hours; now it’s under seven.
- 31% of us sleep less than six hours a night.
- 69% report not getting enough sleep.
- Between 1905 and 2008, children have lost about a minute of sleep each year.
- Being overweight
Ninety percent of all Americans now use electronic devices that emit interfering blue light. Our brains interpret this new blue light as daylight, and thus postpone the signals that induce sleepiness. According to the NYT article, “When ‘dusk’ gets pushed progressively later because of these false light cues, we get a surge of energy rather than the intended melatonin release.”
Those who’d read an e-book released less melatonin and were less sleepy than those who’d read a regular book; their melatonin release was delayed by more than an hour and a half, and their circadian clocks were time-shifted. It took them longer to fall asleep. The next morning, they were less alert. These resetting effects can result not just from prolonged reading but from a single exposure.One Light – Eight Years of Insomnia
I'm well aware of how light can cause insomnia. My longest and worst spell of insomnia occurred when I was in my 60s, and it lasted about eight years. During that time, whenever I tried sleeping in my bedroom, my body would jerk just as I started to doze off, and I'd be awake until 4am or later. I finally discovered that I could get a good night's sleep if I bedded down on the living room couch. Every time I tried to return to the bedroom, the body-jerk insomnia recurred.
It finally occurred to me (d'uh!) that I had no trouble taking my afternoon nap in the bedroom. That led me to wonder if the nighttime culprit might be the streetlight on the other side of the road from my bedroom windows. I installed blackout curtains to replace the Venetian blinds and... Guess what? The body jerking stopped and I could sleep in the bedroom again. Yeah