Katie, the “Wellness Mama” writes:
I firmly believe that light and sleep are two of the most under-used tools for improving health (and that improper management of both are two of the biggest reasons for many health problems). Sound crazy? There is a lot of evidence to support the idea that certain types of light, especially blue light, can impact circadian rhythms and hormone balance in dramatic ways.
The Balance with Blue Light
Until 1879 when Thomas Edison patented the electric lightbulb, artificial lighting didn’t exist and after sunset, people relied on candles, lanterns, and fires for light.
After Edison’s patent, artificial lighting slowly became more widespread, but it has only been in the last century that we’ve seen the dramatic change from candlelight to mobile phone screens. Only three decades ago, a Harvard researcher discovered that light governs our internal clocks and we’ve been slowly learning more about blue light since then.
While a hundred years seems like a long time, it is a short amount of time in the spectrum of human history, and in the last few decades, we’ve started to understand how artificial light affects health. As the research continues, I believe that we will see more evidence that circadian rhythm interruptions from artificial light is partially to blame for many of the problems of modern society. Currently, we already know that overuse of artificial light and the resulting lack of sleep may be linked to certain cancers, increased risk of heart disease, and obesity.
Artificial lighting contains blue wavelengths of light that are absent in light sources like candles, lanterns, and fires. Blue light is known to improve alertness, mood and energy, and is important, but can be harmful if used at the wrong times of day.
How Light Impacts Circadian Rhythm
The body has built in systems that help regular circadian rhythm, and it relies on outside input (especially blue light) to signal times the body should be awake vs times it should be sleep. In other words, there are abut 30,000+ cells in the eye that sense blue light and these cells signal the brain to turn off melatonin production. Melatonin is necessary for sleep, and when it is suppressed at night, when it should be increasing, it can affect sleep quality.
Blue light wavelengths would be seen in nature during the brightest hours of the day and are found in sunlight. These wavelengths are not present in fire or other natural light sources that would have been used at night. Ever sat around a campfire at night? Most people describe natural light sources like fire as being soothing and promoting sleep, largely because of their lack of blue light (and obvious natural beauty).
At the end of the day (pun intended), it is all about timing. Blue light during the day is beneficial in many ways, including:
- Sending the correct signals to the brain for proper melatonin production
- Promoting mood and alertness (in fact, it may be better than coffee!)
- Signaling the body to maintain healthy weight and adrenal function
These are all vital during the day. In fact, my doctor uses the timing of blue light and carbohydrate intake to help balance cortisol and other hormones. Other doctors use blue light therapy during certain times of day to help address sleep disorders, seasonal affective disorder and other disorders.
The problem occurs when a person is routinely exposed to blue light in the evening after the sun has set, especially when this happens daily over long periods of time. This confuses the body’s natural rhythms and signals a reduction in melatonin, which is necessary for sleep.
Harvard Medical School has been studying the affects of blue light:
A Harvard study shed a little bit of light on the possible connection to diabetes and possibly obesity. The researchers put 10 people on a schedule that gradually shifted the timing of their circadian rhythms. Their blood sugar levels increased, throwing them into a prediabetic state, and levels of leptin, a hormone that leaves people feeling full after a meal, went down.
Even dim light can interfere with a person’s circadian rhythm and melatonin secretion. A mere eight lux—a level of brightness exceeded by most table lamps and about twice that of a night light—has an effect, notes Stephen Lockley, a Harvard sleep researcher. Light at night is part of the reason so many people don’t get enough sleep, says Lockley, and researchers have linked short sleep to increased risk for depression, as well as diabetes and cardiovascular problems.
Read the rest of this article HERE.