Insomnia can develop with too little exposure to daylightA daily routine and daily exposure to sunlight help regulate sleep. Research backs this up and I see it in myself. My best sleeps come after days when I get up and out and do the things I do at the usual time.

Last night my sleep went off the rails, and I’m convinced the problem was at least partly related to light. Let me explain.

An Unusual Tiredness

My husband and I were viewing old slides last night, and around 9 p.m. I complained about how tired I was.

“Why?” he asked. Normally at 9 p.m. my evening has barely begun.

I couldn’t explain it. I’d gotten up at the regular time, had coffee, eaten regular meals. Worked in the morning, exercised late in the afternoon. Had a glass of wine before dinner and a decent night’s sleep the night before. Nothing that came to mind could explain how really bone tired I felt.

Staving Off Sleep

Even so, I didn’t go to bed right away. If I’ve learned anything about sleep, it’s that going to bed early can start people like me on a path to perdition. It can lead to:

  • Sleep onset insomnia, or trouble falling asleep at the beginning of the night
  • Sleep maintenance insomnia, or broken sleep with awakenings every hour or two
  • Early awakening insomnia, or waking up in the twos, threes, or fours and being unable to fall back to sleep

So tired though I was, I headed for my favorite easy chair, where I typically read for a couple hours until I’m sleepy enough to fall asleep. Then at some point I went to bed.

A Short Night—Or Was It?

The next thing I knew I woke up in the dark and it felt like morning. I hurried to turn off the alarm clock because my husband was going to sleep in. But when I looked at the time (my clock stays dark at night except when I press the button on top) I saw it wasn’t even close to 5:30, my normal wake-up time. It was only 2:15.

So I went back to bed. At the next awakening, I asked my husband what time it was and he whispered it was almost 5:30. I turned off the alarm.

Only it wasn’t 5:30, and I didn’t turn off the alarm, I later learned from my husband. That whispered exchange must have been a dream. Because when I went downstairs and turned on a light, the clock on the stove said 4 a.m.

What the heck?!

I’d thought my early awakening insomnia was a thing of the past. It was so far from normal now that I was determined to parse it out.

Reconstructing My Day

Two clues lay beside the easy chair where I sat down to read last night.

  • My book: It was open two pages beyond the bookmark, where I’d stopped reading the night before. Guess I didn’t read for very long!
  • Medicine I take every night to help with digestion: Two capsules lay on the desk beside the chair together with a full glass of water, untouched.

Obviously I’d fallen asleep in my chair way earlier than usual. But what had knocked me out so quickly and completely that I forgot to take my medicine? Read just two pages when normally I’d read for at least two hours?

Was Lack of Light the Culprit?

Suddenly it came to me. I had done something out of the ordinary in the middle of the afternoon. I went to a concert, where for two hours I sat under low light listening to Haydn string quartets.

That wasn’t all: the first violinist was super-animated as he played and kept swinging his feet up into the air. Every time those feet came off the ground I thought of a plane taking off, and that image juxtaposed onto the Haydn was jarring. I decided to close my eyes—and kept them closed for the rest of the concert.

So for two hours in the afternoon, at a time when my brain would normally be exposed to light, I sat in near-total darkness. That, added to our half-hour session viewing slides in a dark living room, might have affected my body clock, causing sleepiness to occur earlier than usual and early morning wake-ups.

Bright Light Exposure: Rules to Live By

As ubiquitous as it is, light might not seem like it would have much impact on sleep. But it does. People contending with circadian rhythm disorders have to pay special attention to light, and light or a lack thereof may figure in insomnia, too. Keep these things in mind:

  • Lack of sufficient light exposure during the daytime tends to have a negative effect on sleep duration and sleep quality. Get exposure to sunlight every day by spending time outside or inside near a window.
  • Exposure to bright light early in the morning will help you fall asleep earlier.
  • Exposure to bright light in the evening tends to delay the onset of sleep.


Posted by Lois Maharg, The Savvy Insomniac

Lois Maharg has worked with language for many years. She taught ESL, coauthored two textbooks, and then became a reporter, writing about health, education, government, Latino affairs, and food. Her lifelong struggle with insomnia and interest in investigative reporting motivated her to write a book, The Savvy Insomniac: A Personal Journey through Science to Better Sleep. She now freelances as an editor and copy writer at On the Mark Editing.

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