Your bedroom isn't as safe as you think.
If you have a television... a cellphone... a nightlight... or even a digital alarm clock anywhere near your bed... you may be destroying your sleep and wrecking your overall health.
The culprit is blue light.
Blue light disrupts our natural rhythms. A few years ago, I found myself struggling to sleep after reading on my tablet. It turns out that e-readers (and anything else with screens) emit a lot of blue light.
It not only leaves us tossing and turning, but with too much exposure, it damages our eyes.
And here's the problem... Blue light is everywhere...
Blue-violet light carries the most energy in the visible light spectrum. That's all the wavelengths of energy we can see. Together, they form white light... like you see from the sun and artificial sources of light.
Within the white-light spectrum sit different wavelengths that appear as colors – red wavelengths are the longest and blue-violet are the shortest. The shorter the wave, the higher the energy carried by the light. That's why blue light is troublesome. It carries more, potentially dangerous, energy.
A study from the International Journal of Endocrinology demonstrated how blue light stimulates us to a more awake stage.
The scientists wanted to study blue light's ability to stimulate the release of cortisol and trigger the cortisol awakening response (CAR). You see, our bodies release the hormone cortisol based on a 24-hour cycle. As night approaches, our levels drop and then slowly rise until we wake. Once awake, the CAR takes over, making us alert and ready to start our day.
Researchers took teenagers who got about 4.5 hours of sleep per night and exposed them to either dim light or short-wavelength blue light upon waking. Those exposed to the blue light showed enhanced CAR and improved performance on specific tasks... So much so that blue light is now recommended as a way to "wake up" if you're sleep deprived.
Even more important, the study demonstrated what happens when we expose ourselves to blue light when we're trying to sleep... The enhanced CAR throws our whole cycle off, leading to insomnia.
Cortisol plays an even larger role in our bodies. Cortisol helps keep many processes in balance. For example, it releases protein for our bodies to break down into glucose when we need extra energy. And when we face stress, cortisol surges in to generate the energy we need to run away or fight the perceived threat.
But if we have high levels of cortisol for long periods, it elevates our blood-sugar levels. And it causes us to store up fat, leading to weight gain. Cortisol's role in all of these processes is difficult to explain, but it's a contributing problem to things like diabetes and obesity.
In addition to cortisol, blue light also holds down our melatonin levels. While cortisol helps us wake up, melatonin is the hormone that helps us sleep. As we start to get tired and natural light starts to disappear, our brains signal the release of melatonin. That, in turn, helps us fall asleep.
Humans experience a much higher response to blue light than other wavelengths. The reason is that this type of light triggers a specific photoreceptor in our eyes. These specialized receptors mediate how much melatonin we produce.
It gets worse... Too much blue light damages your eyes.
It causes eye strain at best and macular degeneration at the worst. Macular degeneration is a condition that leads to permanent vision loss.
That's why I wrote more about the biggest sources of blue light and four ways you can keep yourself and your loved ones safe. This research is available to all subscribers of my monthly newsletter, Retirement Millionaire. If you're already a subscriber, click here to access the issue on blue light.
If you aren't a subscriber, this report could save your eyes. And each month, you'll also receive my latest investing recommendations along with insights into health, savings, and living well for less. Click here to get started.