Summer is quickly drawing to a close. Have you spent any time camping outside under the stars? If the answer is no, you might want to think about pulling out that tent from the garage. Camping can be a lot of fun, but that's not why I'm suggesting it. New research shows that time spent camping can help to improve sleep.
Researchers at the University of Colorado Boulder examined the effects of a week of camping on sleep and circadian rhythms, the 24-hour biological rhythms that govern our sleep-wake cycle and other important biological functions. They found that sleeping in the wilderness -- away from artificial light -- for one week reset circadian clocks, bringing them more in line with the natural solar day and night.
Researchers studied the sleep patterns of six men and two women, with an average age of 30. They observed and measured their subjects' daytime and nighttime activity during a normal week. Participants wore wrist monitors that recorded their sleep and their waking activity, as well as their exposure to light and the timing of light exposure. The study subjects then spent another week camping in Colorado's Eagles Nest Wilderness. During their week of camping, they were exposed only to natural light -- sunlight during the day, and moonlight and campfire light at night. During this week, participants had no exposure to artificial light, including flashlights. Researchers took the same series of measurements of their daytime activity, nighttime sleep, and timing and amount of exposure to light. In addition, at the end of each of the two weeks, researchers measured melatonin levels. Melatonin is a hormone stimulated by darkness that works in concert with the body's biological clock to enable sleep. Melatonin levels rise naturally at night and fall back in the morning. Measuring melatonin gave researchers the opportunity to analyze changes to circadian rhythms. They found that compared to a week of normal activity, a week spent camping in the wilderness had a significant -- and strikingly similar -- effect on the circadian rhythms of each and every participant, bringing those rhythms back in sync with the natural cycle of light and dark:
- Participants' biological nighttimes -- when the body's melatonin levels rise and the body prepares itself for sleep -- began an average of two hours earlier when they were camping without exposure to artificial light, as compared to their normal, electrically lit-up lives.
- Artificial light pushes circadian clocks to a later schedule than the solar cycle, which means biological nighttimes start later at night and finish later in the morning. In their normal lives, subjects woke up before their biological nights had ended. When camping, subjects were able to sleep through to the end of their biological nights.
- The group exhibited individual differences in sleep patterns during the normal week of sleep and activity monitoring. Some subjects were night owls and others were early birds. During the week of camping, these individual differences drastically reduced, as all the subjects -- both night owls and early risers -- had their sleep patterns align with the natural cycle of day and night.
Why does this circadian alignment matter? Circadian rhythms are an ancient aspect of most living organisms, present in the earliest evolutionary ancestors to humans. These rhythms developed in relation to the solar day and night, responsible for regulating sleep as well as other important biological processes, including hormonal and metabolic functions. Normal functioning of circadian clocks is essential to human sleep and health. The past 100 years or so of modern industrial life has posed serious challenges to these ancient and fundamentally-important biological rhythms, specifically in the form of electric light. In these decades of industrialization, artificial light has proliferated -- lighting up the world, making nighttime darkness largely optional for the first time in human history, and disrupting our circadian rhythms. Exposure to light at night inhibits the release of melatonin, throws the 24-hour circadian rhythm out of sync with the solar day and alters our natural sleep-wake cycle. This latest study shows that within a week of sleeping and waking in natural light -- without the presence of artificial light -- our bodies return to a natural alignment with the 24-hour solar cycle. These results reveal just how powerful these biological rhythms are -- and how significant a challenge artificial light can pose to their proper functioning.
Disruptions to circadian rhythms interfere with restful sleep and are associated with a number of serious and chronic health problems, including heart disease, cancer and diabetes. People whose daily lives do not adhere to a traditional day-night schedule, including millions of people employed in shift work and others who experience jet lag from frequent travel, are at elevated risk for disruptions to circadian function and the health problems associated with them. But our circadian rhythms are sensitive, and it doesn't take disruptions as significant as overnight shifts or cross-country flights to weaken and throw off our circadian clocks. Watching television, reading tablets, scrolling our smartphones or laptops -- these common activities done later in the evening hours can throw circadian rhythms off kilter, making it more difficult to get sufficient amounts of high-quality, restful sleep.
What's the remedy for this modern, electronically-lit problem facing our sleep? I am certainly not suggesting a return to lamplight. The goal is to work within the realities of our culture and individual lives, to make thoughtful choices and create balanced routines with sleep and health in mind. Here are some suggestions for ways you can strengthen your circadian clock and improve the quantity and quality of your sleep:
1. Get some sun. Exposing yourself to sunlight in the first half of the day will reinforce your circadian rhythms and can help counterbalance the effects of exposure to artificial light. Spending as little as 10 minutes outdoors in the morning or at midday will help push your circadian clock slightly earlier, more in sync with the solar day. You'll feel more alert during the daytime -- and more ready for sleep at night.
2. Make sure your bedroom is dark. A darkened bedroom is critical for falling asleep and for sleeping well throughout the night. Hang curtains or shades to fully block any outside lights. If you need to get up to use the bathroom during the night, use a small nightlight to help you find your way without turning on an overhead light.
3. Keep electronic devices out of the bedroom. Tablets, phones and laptops -- these devices emit light that when used at bedtime can interfere with your sleep cycle. The easiest and most effective way to prevent this is to keep your bedroom gadget and screen free. Make the last hour before bed an electronic curfew/digital-free time to allow your body to prepare for sleep.
As this research shows, sleeping in the natural world can help reboot your sleep cycle. If you're looking for sleep-friendly vacation ideas, camping should be at the top of your list.
Michael J. Breus, PhD
The Sleep Doctor®
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