Was My Insomnia Due to Lack of Light?

A 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.

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.

 

Awake in the Middle of the Night

The bed—so sleep experts maintain—should only be used for sleep and sex. People who can’t sleep should get up and do something: iron shirts, look at picture books, plan a backyard stupa. Anything, for God’s sake, but toss and turn among the sheets.

I know I should follow this advice. But every fiber of my body cries out for staying flat on my back.

The bed—so sleep experts maintain—should only be used for sleep and sex. People who can’t sleep should get up and do something: iron shirts, look at picture books, plan a backyard stupa. Anything, for God’s sake, but toss and turn among the sheets.

This bit of advice has always put me off. Especially when I wake up in the middle of the night and can’t fall back to sleep, I’m bone-tired and brain-dead. I can barely face getting out from under the warmth of the covers to go to the bathroom, let alone contemplate walking downstairs, turning on a light and settling down with a book. Every fiber of my body cries out for staying flat on my back.

Making Hay While the Darkness Reigns

But I’ve met insomnia sufferers of the middle-of-the-night-awakening type who decided at some point that they were not going to take their wakefulness lying down.

My former colleague Claudia is a journalist with a greeting card business on the side. She used to lie awake fretting when she couldn’t fall back to sleep. Now when she wakes up at 1 a.m., she goes upstairs to make birthday cards.

“It’s like playing around,” she says. “It takes my mind off everything, and sometimes I think it helps me mellow out a little, too.” After working a couple of hours on her cards – an activity she says is fun but not cerebral – she crawls back into bed again and can usually get a few more hours of shut-eye. She’d rather deal with insomnia this way than take sleeping pills.

Marty is another example. Self-employed, he goes to bed around 9 p.m. and uses the time he’s awake in the middle of the night to work on an online newsletter. “I do my best writing between 2 and 5 in the morning, “ Marty says. Then he goes back to sleep for another hour and a half. He’d like to sleep more, and to get all his sleep at one go, but his body seems to have different needs.

Bimodal Sleep in Nights Past

Historian A. Roger Ekirch claims this pattern of broken sleep was actually common before 1800, when people lived without artificial lighting in their homes. Ekirch has found several references to nights in which people took their “first” sleep from about 9 or 10 p.m. to somewhere past midnight. Then they got up to brew a tub of ale or chat with neighbors, or they stayed in bed to pray, make love or meditate on dreams. At last they fell into a “second” or “morning” sleep that lasted until dawn.

Experiments conducted by sleep researcher Thomas Wehr in the 1990s suggest this bimodal pattern of sleep is the pattern humans might well fall into today in the absence of artificial lighting. Our modern lights-out period lasts for seven or eight hours a day year-round. But in temperate climates in the pre-industrial era, during the winter months when darkness lasted 14 hours, people spent a lot more time in rest and relaxation.

When Wehr re-created these conditions by giving his experimental subjects a 14-hour sleep window, they settled into a routine in which their sleep fell into two distinct periods. One came at the beginning of the “biological” night and one at the end, with a period or periods of quiet wakefulness in between. Wehr concluded that bimodal sleep may actually be more “natural” than the consolidated sleep period that is the norm today.

The notion may not be reassuring to insomniacs unable to turn middle-of-the-night awakenings to their advantage, or whose work or families demand that they be up at the crack of dawn. Nor does it jibe with the thinking of most sleep experts, who suggest that a consolidated period of sleep is for the insomniac the Holy Grail. But if segmented sleep really does come more naturally to some poor sleepers, then the Claudias and Martys may be better off going with the flow.