How light affects sleep
Have you ever woken up just minutes before your alarm goes off and marveled at your body's sense of time? Humans (and most living creatures) have an internal clock that mirrors nature's cycles of day and night. More ►
Nestled deep in an area of the brain called the hypothalamus, this timekeeper regulates many of our body's functions, such as sleep, energy, and hunger.
Sunlight detected by cells in the retina of the eye sends messages to the brain that keep us in a roughly 24-hour pattern. These light cues trigger all kinds of chemical events in the body, causing changes in our physiology and behavior. For example, as evening approaches and the light in our environment dwindles, the hormone melatonin begins to rise and body temperature falls—both of which help us to become less alert and more likely to welcome sleep. With the help of morning light, melatonin levels are low, body temperature begins to rise, and other chemical shifts, such as an uptick in the activating hormone cortisol, occur to help us feel alert and ready for the day.Stephan FK, Zucker I. Circadian rhythms in drinking behavior and locomotor activity of rats are eliminated by hypothalamic lesions. Proceedings of the National Academy of Sciences. 1972; 68(6):1583-1586.
Making your room dark
Light and darkness are powerful cues that tell your body it's time to rest, or get you ready for a productive day. So it's no surprise that light in the bedroom (as well as light peeking in from outside) has an impact on the quality of your sleep. More ►
Artificial light after dark can send wake-up messages to the brain, suppressing the production of the sleep-inducing hormone melatonin and making it harder to fall asleep and stay asleep. In fact, a recent study showed that even bright room light could have this chemical effect. And early sunrays begin to activate the body and can cause some of us to rise before we're ready.
With a little thought and creativity, though, you can use the body's light sensitivity to your advantage. Consider low-wattage, incandescent lamps at your bedside to help you wind down in the hours before sleep. Survey your room for any other sources of artificial light, for example, streetlamps or porch lights, or even the glow from the power buttons of electronics like TV's or bright alarm clocks. Consider blocking these to make the room completely dark while you sleep. If you go to the bathroom during the night, do so by nightlight, instead of turning on stronger overhead lights.
If you can wake up rested with the sun after 7-9 hours of sleep, then by all means welcome the early morning rays. If not, use darkening curtains or shades to keep your body in sleep mode until it's time to wake up and start the day.
How electronics affect sleep
Our world is full of gadgets. For both work and entertainment, technology use is increasingly popular, and the evening hours are no exception. For example, a recent poll by the National Sleep Foundation found that 95% of people use some type of computer, video game, or cell phone at least a few nights a week within the hour before bed. More ►
But scientists are now finding that light from electronics has the potential to disrupt sleep, because it sends alerting signals to the brain. The circadian rhythm seems to be especially sensitive to light with short wavelengths—in particular, blue light in the 460-nanometer range of the electromagnetic spectrum. This light, which is given off by electronics like computers and cell phones, and also by energy-efficient bulbs, has been shown to delay the release of melatonin. In other words, electronics could keep you feeling charged past bedtime.
If you have difficulty falling asleep or staying asleep, consider keeping electronics out of the bedroom and turning them off—especially those used at close range—for at least an hour before bed. It can take some time for the body to come down from technology's alerting effects. Protect your evening wind-down time by reading a book, for example. Let your body chemistry settle for the night.
- National Sleep Foundation. 2011 Sleep in America Poll: Communications Technology and Sleep. Washington (DC): The Foundation; 2011 Mar 7. ►
- Evening exposure to a light-emitting diodes (LED)-backlit computer screen ►
- Exposure to Room Light before Bedtime Suppresses Melatonin Onset ►
- Limiting the Impact of light pollution on human health ►
Sunlight and sleep
Light is a powerful guide for your body. In part through the connections between the eyes and the brain's biological timekeeper, light rays influence chemistry and behavior and keep us in sync with the ebb and flow of the day. More ►
Think about it: humans evolved spending a lot of time outside, where they were exposed to light beginning with the rising sun. In our modern world we spend more time indoors, but sunlight still helps regulate our sleeping patterns.
When you're ready to begin the day, exposing your body to the sun will not only help alert the brain and set you in motion, it will also help you sleep later on. Have blinds or curtains that can cocoon you in darkness by night, but that you can easily pull back to bathe the room in sunlight when you wake. Before you start the day, spend some time in the light, and remember to give your body doses of sun throughout the day when possible.
If you need to wake before the sun comes up, you can find dawn-simulating alarms, or even use lights intended for seasonal affective disorder—these are particularly helpful during the winter when the sun rises later.Close ►
Help your child sleep by controlling light
As you think about crafting a sleep-friendly bedroom environment, remember that our little ones' bodies are also very sensitive to light cues. Use your knowledge of light and dark to help your kids sleep better too. More ►
Screen time may activate the brain, so limit it in the hours before bed and keep technology out of your child's room. Instead, arrange comfy pillows in a clutter-free, calming space (although never in the crib, for safety reasons) so she can read and relax. When you start your bedtime routine, keep the lights low to help your child wind down, and after lights-out, use a nightlight in the bathroom for late evening or nighttime potty trips. Scan the room for any additional sources of light, such as those from electronics, and if your child likes to sleep with a nightlight, use one that is quite dim. Room darkening shades and curtains can be very helpful for blocking evening light during the summer, streetlights, as well as morning rays (especially handy if you have an early riser). These can also be useful to darken the room for daytime naps.
If you have a baby, managing her exposure to light and dark is key in the early months while the circadian rhythm is maturing. In the morning, raise the shades and take her outside for a dose of indirect sunlight. As bedtime approaches, make the lights dim and keep them low during the night for feedings.Close ►
Bedroom light and shift workers
Plenty of jobs come with hours outside the typical 9 to 5 day. Shift workers—for example nurses, doctors, pilots, drivers, and police officers—are estimated to comprise almost 15 percent of the U.S. work force. More ►
An irregular work schedule can be taxing on the body. When you work late at night and miss out on daytime light, for example, it confuses the brain, disrupts the circadian rhythm and can make for sleepiness, insomnia, and other health problems. On top of that, many shift workers have rotating schedules, which means that their bodies are constantly forced to readjust to new rhythms.
If you need to sleep and wake at atypical hours, managing the light in your bedroom can help. When you're winding down for sleep, dim the lights and try to limit your use of electronics. Use special room darkening shades or curtains to block daylight and make your room completely dark for sleeping or try wearing an eye mask.
Room design for better sleep
Imagine your bedroom as a sanctuary. When you walk in—or simply think about your bedroom—it should make you feel relaxed and peaceful. Taking care of your sleep environment and putting thought into its look and feel is important, and could help you welcome more restful nights. More ►
Start by de-cluttering your room and creating a clean and relatively ordered space (not surprisingly, piles of unsorted papers could make you anxious or restless). Arrange your furniture in a way that feels natural and visually pleasing to you. Try to keep computers and TVs out, so that you come to know your bedroom as a haven for sleep, free of distractions.
Choose wall colors that elicit warmth and calm. Although researchers have studied the psychology of color and some believe that certain hues affect our mood (for example, red being stimulating), no one knows your color-feeling connections better than you do. Pick colors, artwork, blankets, and so forth that are soothing to you.
did you know?
73% of Americans rated a dark room as important to getting a good night’s sleep in the National Sleep Foundation’s 2012 Bedroom Poll.