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.

 

Insomnia at the Approach of Summer

It happens every year in the spring: someone writes in to The Savvy Insomniac complaining of an inexplicable onset of insomnia. No stress is involved, no abrupt change in circumstances.

If you find yourself experiencing insomnia at about this time every year, the problem may have to do with lengthening days. The solution may lie in reducing your exposure to sunlight.

To conquer insomnia in the summer, reduce light exposureIt happens every year in the spring: someone writes in to The Savvy Insomniac complaining of an inexplicable onset of insomnia. No stress is involved, no abrupt change in circumstances.

Here’s how a reader described the problem this year:

 

Every year at the same time (between the end of April and the end of June, I don’t know why?), my sleep becomes very capricious. I don’t sleep when I go to bed and, inexorably, I have to start again a new ‘sleep restriction.’ I feel pretty jaded because it’s difficult!

Whenever you’re having trouble sleeping, it helps to tighten up your sleep window and stay out of the bedroom until you’re really sleepy. But if insomnia tends to strike at about this time every year, the problem may have to do with lengthening days. The solution may lie in reducing your exposure to sunlight.

Seasonal Variation in Light Exposure

The further away from the equator you live, the greater are the seasonal differences in your exposure to sunlight. Not many comparative studies have measured how these seasonal variations in day length affect people’s sleep. But one study published in 2012 compared the sleep timing and quality of people living in Norway (far from the equator) and others living in Ghana (close to the equator) in the winter and the summer.

Ghanaians rose and went to sleep at about the same time in both seasons. The Norwegians rose 32 minutes earlier (and went to bed 12 minutes earlier) in the summer than in the winter, suggesting that seasonal variation in day length can affect our internal clocks. When the days are longer and sunrise is earlier, people may tend to get up (and go to bed) a little earlier than they do in the winter.

Seasonal Affective Disorder

However, the Norwegians in this study experienced more insomnia and reported lower moods in the winter when the days were short. This finding aligns with the results of other research—from Norway, for example, and from Finland—showing that in the late fall and winter, insufficient exposure to daylight is associated with seasonal affective disorder, or SAD, and trouble sleeping.

I see anecdotal evidence of this phenomenon every year. Readers write in complaining of insomnia that typically starts in November or December. The solution to this seasonal insomnia is bright light therapy, appropriately timed.

Too Much Light?

Other people report that their insomnia typically occurs in the spring and summer. There’s a dearth of research on this phenomenon, but I suspect that excessive exposure to daylight could trigger insomnia in those who, for whatever reason, are particularly sensitive to light. Light blocks secretion of melatonin, a hormone helpful to sleep, so restricting your exposure to bright light early in the morning and later in the evening may help.

Here are suggestions for how:

  • Install light blocking curtains on bedroom windows so the morning sunlight doesn’t wake you up too early
  • Draw blinds and curtains in your home before the sun sets and keep indoor lighting low in the evening
  • Wear sunglasses if you’re outside in the sunlight very early in the morning or after about 8:30 p.m.
  • Steer clear of devices with screens in the run-up to bedtime.
  • Buy a comfortable eye mask and wear it when you sleep

If you find eye masks uncomfortable, perhaps a towel wrapped around the eyes and head will do the trick. A few years ago a neuroscientist–sleep researcher told me she was super sensitive to light at night, and this was her way of solving the problem. Do whatever works!