Natural light and sleep

In his brilliant book, At Home: A Short History of Private Life, American author Bill Bryson writes “We forget just how painfully dim the world was before electricity. Open your refrigerator door and you summon forth more light than the total amount enjoyed by most households in the eighteenth century. The world at night for much of history was a very dark place indeed.”

In his observations, Bryson sparks a thought we don’t often reflect upon – how is the abundance of artificial light in our modern lives affecting our sleep? Our increased use of electrical light is thought to have caused us to stray far from our natural circadian rhythms and disrupt our sleep patterns. A possible contributor to poor quality sleep, a US study has sought to ascertain whether humans return to their natural light/dark sleeping cycles with a week of camping exposed to only natural light.

The study was conducted in the Rocky Mountains, Colorado and recorded participants in their daily sleep routines for one week, before setting them up in tents with natural light and campfires for the second week. The study found that reducing electric light and increasing exposure to sunlight shifted the internal clock earlier, making it easier to wake in the morning. The average natural light exposure of participants also increased more than four times during the second week.

While eliminating all of our electric lights is hardly practical, it certainly flies the flag for a week or two of refreshing camping trips each year to reset the body clock.