You may remember the blue-blocking sunglasses that were popular in the U.S. in the 1980s. The glasses, with their amber-colored lenses, had a bit of a cult following and were perhaps best known for how clear they made regular objects appear.

They were promoted by Joel Sugarman who is actually a friend of mine and regular reader of this newsletter.

However, many are not aware that these glasses were originally designed for the NASA space program. Astronauts need powerful eye protection in outer space, where ultraviolet (UV) rays from the sun are incredibly strong.

A sunglass manufacturer developed a special design that blocked not only the UV rays but also blue rays.¹ The glasses had the desirable "side effect" of making objects appear sharper, but the real benefits of blocking blue light are only beginning to be understood.

Far beyond the benefits to your visual clarity, blocking blue light serves an important biological purpose, helping to regulate your internal clock to control sleep patterns and other body functions. Quite simply, avoiding blue light at night is crucial to protecting your health.

Why Exposure to Artificial Blue Light Needs to Be Avoided

Exposure to artificial light is one of the largest often-overlooked health risks of living in the 21st century. Your early ancestors had no such worries, as their day started and ended with the rise and fall of the sun, which synchronized perfectly with their circadian rhythm.

Today, your body is still attuned to this internal clock. In the morning, bright, blue-light-rich sunlight signals to your body that it's time to wake up. At night, as the sun sets, darkness should signal to your body that it's time to sleep.

The problem is that most people living in developed countries no longer go to sleep when the sun sets.

Instead, we turn on LED lights, computers, televisions, tablets and smartphones, all of which expose us to varying amounts of blue light at a time of day when there's supposed to be next to none. Your body is understandably confused as a result.

It's now becoming clear that one of the least expensive and simplest ways to protect your body's internal rhythm, and thereby support healthy sleep and a lowered risk of many chronic diseases, is to wear blue-light-blocking glasses not just at night but anytime you are exposed to artificial lights.