The Importance of Light and Darkness in Mental Well-being

Understanding Sleep Disorders and Their Relationship with Light and Darkness

Sarah (all names are fake and the stories are published at the request of the patients) can't get out of bed. When I want to let her know that she's free an hour on the day she asked to come, I know I have to write her at six in the morning, before she goes to bed, or at six in the evening, the only time she's pretty sure awake. Guy, on the other hand, goes to bed around midnight and wakes up in horror in complete darkness, putting off the moment when he will check the clock and discover that it is not yet four in the morning. He knows that his day begins the moment he opens his eyes, and in most cases, it is a very long and frustrating day.

One sleeps too much, one sleeps too little. Do their sleep difficulties indicate a problem with the same biological mechanism? Is Sarah just a "night type"? Where is Guy's mistake?

I'm not a sleep researcher, but it's clear to me that a good night's sleep at the right times of the day is an essential part of mental well-being, even if sometimes it's hard to tell if it's a cause or an effect. And good sleep is also intimately related to our relationship to darkness and light.

This ratio changes over the years. Many children are afraid of sleep itself, which simulates death, lack of control, and more. But the fear is not only of sleep but also of the dark. Apparently, throughout life, most of us prefer light. In fact, we have a kind of hunger for light. I had the opportunity to think about the topic in preparation for a conversation in the "Hard Question" corner on Shai Piron and Inbal Gazit's radio show. In preparing for the conversation, I realized that I think what really scares us is not the darkness but a situation where we will have to see and cannot see.

It is also easier for women to give birth in a space that is not too lit, and massage, various mind-body treatments, and heart-to-heart conversations tend to be experienced as more successful when they do not take place under fluorescent lights. Many different processes take place in our body that need darkness. That is, we need light but also darkness.

And we need not only darkness itself but also sleep. We go astray without light just like Sarah, but derail like Guy without sleep. In fact, although we still don't know exactly how sleep is a critical part of our health (there are theories about its role in restoring and repairing cells, and those that focus on sleep's role in memory formation), we do know that we will cause the death of an animal if we chronically deprive it of sleep.

I mean, we need both light and darkness, but we also need to receive them in a very specific way, otherwise, we get out of sync, like Sarah and Guy. The biological clock (Circadian Rhythm) is different from the solar day (a cute detail is that the name of this system reflects its inaccuracy: circa means "about" and dia means "day," that is, already in the title we learn that it is a rhythm of "about a day"). The solar day is exactly 24 hours long, but our biological day is approximately 24.2 hours long. Exposure to light at the right time and avoiding exposure to light at the right time are necessary to keep us in sync with the solar day.

0.2 hours doesn't sound like much—a total of 12 minutes. But like a clock that doesn't reset, it's 12 minutes every day. If we do not maintain the connection between our body and the solar day, then within five days, a gap of one hour will open between us and the environment, and within a month, we will already be living with a gap of six hours from reality. In the case of Sarah, who went to bed at six in the morning and got up at four in the afternoon, she was unable to get out of her depression for months and was already living completely opposite of the environment.

Sarah felt that it was easier for her to deal with the world at night, and that the environment was less dangerous for her (there are fewer emails and less chance of encountering stressful neighbors in the stairwell), but getting out of sync with the environment has serious effects. Going back to our basic survival for a moment, an animal that sleeps while the entire jungle is awake decreases the chance of passing its genes on to the next generation, to put it mildly. And even in the modern jungle, people tend to look down on those who sleep during the day. There are various reasons for this, but among other things, I assume that most of us have formed the impression that people who are awake during the day and sleep at night are more prosperous than those whose cycles are the opposite.

By the way, there are those who believe that they are simply "night types," but the research is not conclusive on the matter. A fascinating example of this is an experiment conducted with teenagers, who are known for having difficulty falling asleep at "normal" hours and having difficulty waking up along with the rest of humanity. I heard about this research, as well as many of the fascinating ideas presented here, in studies and interviews given by the chronobiologist (researcher of periodic phenomena) Dr. Samer Hattar. Hattar said that in this experiment, teenagers were taken for a week of camping in nature, where they were told that they could go to sleep and wake up at whatever time they wanted but allowed them to be exposed to natural light only, that is, to the solar day. The vast majority of participants synchronized to the solar day within a week, and the fascinating thing is that the synchronization was maintained for a very long time afterward.

So if we return to the question of light and darkness, it seems that we seek and ask for light. There is support for this in our language—we talk about "the light at the end of the tunnel" and a loved one is "the light of my life." But the emphasis on light may be related to the fact that naturally, we are only aware of the conscious part of our vision, the one that produces images. In practice, our mental and biological well-being—with all the overlap between them—is based on exposure to light and avoiding exposure to light at the right stages of the day.

And by the way, exposure to light at the right times is not enough. The model that is considered to have the greatest effect of light on our body and soul emphasizes that we must also adjust our activity level and our food consumption level to the cycles of day and night. There are more and more studies according to which people like Sarah and Guy should schedule their physical activity and eating for daylight hours so that they can bring their bodies and minds to maximum balance. And even if we don't suffer from getting out of sync on the levels of Sarah and Guy, most of us will experience physical and mental improvement if we dim the lights at home in the evening (a bit like on an airplane), go out in the morning to walk for fifteen minutes in the natural light, and of course stay away from screens as much as possible before bed.

When I was studying anthropology, I remember the huge impression that Mary Douglas's insight left on me: dirt is material that is out of place. That is, sand in the sea is fine, but sand in the house is dirt. Food on a plate is beauty, but food in the hair is dirt. Borrowing this concept, it can also be said that problems with emotional hygiene—that is, mental distress—are often associated with light and darkness that are out of place.