Sleep Deprivation: Bright Lights and the Circadian Rhythms
Homo sapiens has always slept a lot, especially during the winter, but now we’re sleeping less than we ever have. Instead of sleeping for a minimum of 8 or 9 hours each night, many people are only sleeping 5 or 6. It’s not enough. The common issue of sleep deprivation is intrinsically related to high cortisol levels and, surprisingly, bright lights.
The way we sleep affects our ability to recover at the cellular level. While we sleep our organs regenerate, our muscles strengthen and rebuild and all the systems in the body are rejuvenated. Our immune system switches into top gear. HGH, the human growth hormone, is released, which helps the body burn fat. The parts of the brain responsible for emotional and social processing relax, allowing us to confront the following day without stress. Information and memories are reorganized. Interestingly, LTP or Long Term Enhancement, occurs during the REM phase and becomes more dependent on sleep as learning complexity increases – so, the more we’re learning, the more we need to sleep!
Like every other living creature on the planet, our sleep and wake cycles are determined by the Circadian Rhythms which are governed by the rising and the setting of the sun. The presence or absence of light stimulates the release or suppression of the hormones melatonin and seratonin. When receptors in our skin cells register that light is fading, melatonin is released in a process known as Dim Light Melatonin Onset (DLMO). Melatonin makes us sleepy and promotes long and deep sleep.
With the morning light, our genes reduce melatonin and increase levels of seratonin and cortisol. These two hormones allow us to feel refreshed and energized for the new day.
Hidden Darkness: Where Has the Night Gone?
One of the big problems of modern life is that we’re not exposed to natural darkness. Electric light is a very recent phenomenon. In 1880 Edison patented the incandescent light bulb. In 1925 only half the homes in the United States had electric light. Less than 100 years ago, after sunset the only light we were exposed to was the soft, soothing light of candles and oil lamps.
Now it’s possible to forget to turn on the headlights of the car because the roads are ultra illuminated. Now, we have to do something to create a dark environment and override light pollution – and it’s important that we do so because artificial light of all kinds interrupt the Circadian Rhythm.
Blue Light and Sleep Deprivation
The light throughout our homes and the light emanating from our digital and electronic devices deceive the body into thinking that it’s still daylight. The power of light is measured on the Kelvin temperature scale. On this scale, the blue light that emits from the monitor of a computer, tablet or smartphone is stronger than the midday sun.
When we’re under the influence of blue light, levels of melatonin can’t rise. Rather, cortisol levels remain high in order to keep us awake, alert and active at a time when we should be relaxed and sleepy. By now we well know the effects of high cortisol: cravings for sugar and carbohydrates, fat storage patterns, inflammation. To these, we can now add the effects of an interrupted Circadian Rhythm. Sleep deprivation means more than nights of insomnia. It compromises the immune system, decreases cognitive function and, of course, decreases energy levels the following day, all of which prevent us from living a full life.
How to Prepare for Sleep
To sleep well, it’s not enough to simply go to bed. Like relaxation in general, we need to develop and practice good sleep preparation habits. We need to dim the lights. Wearing glasses with yellow lenses and lighting yellow lamps is a good way to decrease the effects of blue light and allow melatonin levels to rise. Evenings should be passed in tranquil ways – easy conversation, soft music, relaxing hobbies.
Most importantly, we should switch off all devices a couple of hours before bedtime. In fact, we need to severely limit our use of them. This isn’t just because of melatonin, sleep deprivation and the Circadian Rhythms. It’s also because technology, as you’ll see in the next post, is chemically addictive.
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Sleeping Woman Photo by Vladislav Muslakov on Unsplash | Woman watching Sunset Photo by Anatol Lem on Unsplash | Street Lights Photo by claire jones on Unsplash | Woman in bed with laptop Photo by Victoria Heath on Unsplash | Woman sitting on bed in the dark Photo by Ben Blennerhassett on Unsplash