In the two weeks since retirement, I've been plagued by insomnia. I go to bed, feeling tired after a strenuous day, but just can't fall asleep.

This is extremely unusual for me, since I normally fall asleep almost immediately and sleep soundly. I wake up a couple of times during the night--though come to think of it, "wake up" may be too generous an expression. Maybe "surface" might be more appropriate, coming to consciousness long enough to pull the blanket up higher if I'm cold, turn over, and/or go to the bathroom (not in that order). Then instantly off to snoozeland again, blissfully relaxed.

I've been a bit worried about the insomnia, because I hear tell that "older" people often sleep poorly. I'm not ready to be "older" yet. So I did some research.

Well, it turns out that looking fixedly at the screen of an electronic device--smartphone, tablet, computer, TV--just before bedtime correlates with being unable to fall asleep easily. Seems that the visual input keeps the brain from releasing the sleep-inducing hormone melatonin.

I had been using the computer right up until bedtime since retiring. Maybe that was the problem. So I switched to reading for an hour or so before going to bed (the book I'm reading is definitely not soporific) and fell asleep like a baby. Literally. Awake one minute, out like a light the next.

No pharmaceuticals or schedule change required.