It may be time to buy blackout shades for your home – especially if you live on a well-lit street or in a busy part of town. Because the light from street lamps can really mess with our sleep.

The research was conducted by sleep scientist Dr. Maurice Ohayon, from Stanford. His research spanned 8 years and involved 15,000 people. And he found that the nighttime environment of people in cities was three to six times brighter than that of people in small towns and the countryside. And people who lived in bright areas were more likely to sleep less than six hours a night and then have to deal with daytime fatigue.

Basically, light is the biggest factor in regulating our circadian rhythm. And many streetlights today are LEDs, which give off a blue light that suppresses our sleep hormone melatonin. You can tell if you live in an area with older lights if they give off a yellow or orange glow. But Dr. Ohayon says the ambient blue light from the newer LED street lamps are basically as bad for your sleep as using a smartphone or tablet before bed.

So bottom line, if you live in an area with a lot of outdoor light – use blackout shades or a sleep mask.

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