Sleep with light on


Too Much Light: Ruining Not Just Your Sleep But Your Health Too

Falling asleep with the TV on may ward off the bogeyman, but research suggests that, over time, too much light at night could interfere with healthy sleep, possibly increasing your risk of sleep disorders and other health problems. According to emerging research, sleep disorders and nighttime lighting may be making us fatter, more depressed, and more likely to develop cancer.

You’re not alone if you find yourself falling asleep to the glow of the TV or a computer screen. But, says insomnia researcher Colleen Carney, PhD, associate professor of psychology at Ryerson University in Toronto, her patients’ reluctance to turn off these light sources in order to get a better night’s sleep gave her an idea that research later confirmed: The need for the TV, a spouse, or a light source to feel comfortable falling asleep may be rooted in a fear of the dark.

Carney and her team looked at the nighttime and daytime startle responses of close to 90 undergraduates. Those who said they had trouble sleeping were also more likely to startle in response to loud noises in the dark. Since the researchers excluded people who had post-traumatic stress disorder (PTSD), a condition in which individuals are already hyperalert, they concluded that the results suggest that people who say they sleep poorly might have a low-grade fear of the dark. And, Carney says, the best way to get over that fear is to gradually spend more time in the dark until falling asleep in the dark gets easier.

Light’s Effect on Sleep/Wake Cycles

Our body’s basic rhythms, including our sleep/wake cycles, are tied to light exposure, argues sleep researcher Christopher Drake, PhD, of the Henry Ford Hospital in Detroit. Drake has published research in Chronobiology International that explores changes in these rhythms in shift workers who are faced with the challenge of sleeping during the brightness of day and working in the poorly lit night.

Ordinarily your body produces the soporific (sleep-inducing) hormone melatonin as a preparation for sleep. But, says Drake, “light actually suppresses melatonin.” Melatonin suppression caused by light is at the heart of much of the research linking nighttime light to sleep disorders and poor health. The effect of even a brief amount of light is long-lasting. Bright light late in the evening — around midnight — can push your sleep/wake cycle back by half an hour or so, making you sleepy later in the evening the following night. On the other hand, bright light early in the morning, when you first wake up, advances your cycle, bringing on sleepiness earlier. For people whose light exposure and sleep habits are chaotic, the end result is a disordered sleep/wake cycle and related poor health outcomes.

The connection between nighttime lighting, sleep disorders, and health risks is so strong that the American Medical Association recently issued a statement emphasizing the risk and calling for the development of nighttime lighting technologies that would not interfere with the body’s basic rhythms. The World Health Organization already recognizes shift work as a risk factor for developing breast or prostate cancer, specifically because of the way in which light at night negatively affects all the body’s cycles, including sleep and wake cycles.

If overcoming your fear of the dark isn’t reason enough to turn out the lights, consider the impact of sleep disorders and poor sleep on your health. You’re risking:

Depression. Sleep disorders are strongly linked with the risk for depression and the experience of depression. Research published in the journal Molecular Psychiatry shows that even dim lighting at night — the equivalent of a night-light — can increase physiological changes that lead to depression in rodents. “In hamsters, dim light at night provoked depression-like behaviors and changes in the brain. This could be occurring through disrupted circadian rhythms or suppression of melatonin,” says researcher Tracy Bedrosian, a PhD candidate in the department of neuroscience at The Ohio State University in Columbus. The good news is that the symptoms reversed themselves when normal lighting conditions were restored.

Cancer. Light at night (known to researchers as LAN) is a significant risk factor for developing breast cancer, according to researchers who reviewed data from 1,679 women and published their findings in Chronobiology International.

Reproductive health. Publishing in Epidemiology, researchers report that rotating shift work, which leads to increased exposure to light at night, appeared to disrupt the menstrual cycles of female workers. The research involved 71,077 women who participated in the Nurses’ Health Study II. About one in five participants worked a nontraditional shift for at least a month in the two years before the study. The more time spent on shift work, the more irregular the cycles became. Researchers theorize that the disordered exposure to light and chaotic wake/sleep cycles could interfere with fertility over time.

Obesity. According to research published in the Proceedings of the National Academy of Sciences, even dim light at night may be reorganizing other physical rhythms, such as eating schedules. Researchers exposed mice to dim light at night over eight weeks and found that the mice gained more weight than those not experiencing nighttime lighting. And, say the researchers, at least in mice, this gain appeared to be due to disordered eating. In contrast, mice exposed to light at night, but with food limited to scheduled eating times, did not gain excess weight.

How to Face the Dark

Whether you leave a light on purposely or accidentally because you often drift off to sleep while watching TV, here are steps you can take to limit the way that light may be affecting your sleep:

Seek light when you wake up. Bright light — ideally sunlight — when you wake up will help your body set its internal clock, especially if you keep a consistent wake time.

Turn off all screens. TV, computer, smartphone, tablet, reading device — turn them all off when you go to bed. Better yet, turn them off at least an hour before. Even their seemingly innocent glow interferes with sleep, possibly because they shine directly into your eyes.

Face your fear of the dark. If you suspect that you have a darkness phobia, you can overcome it, often with the help of just about any self-help book on conquering phobia through exposure, says Carney. If you’re still feeling anxious at the thought of falling asleep without the TV on or a comforting light, seek help from a therapist trained in cognitive behavioral therapy, a therapeutic approach that has been shown to work well for both sleep disorders and phobias.

Limit light while sleeping. In addition to turning off all the lights under your control, you might need to put up light-blocking shades or curtains to keep ambient light, such as your neighbor’s porch light, out of your room. You might even try wearing a sleep mask over your eyes.

Pick red or orange night light. Bedrosian points out that the depressive effects of night-lights in hamsters would occur in humans with lights about four times brighter, so outlet night-lights should be fine for you. However, if you’re still concerned, red/orange light does not affect the circadian system in the same way as white/blue light, so using colored light might be an effective option, she says. The American Medical Association recommends dim red night lighting.

Don’t turn on lights at night. If you have to get up from sleep to use the bathroom or for other reasons, do not turn on bright lights. Instead, use a flashlight or plan ahead and place red/orange night-lights in appropriate places in your home.

Learn shift work sleep strategies. About one in five people works a schedule other than the traditional 9 to 5, according to the Bureau of Labor Statistics. People who work at night and have to sleep during the day face additional light-control challenges. Their best bet, says Drake, is to seek out brightly lit environments in the wee hours (midnight until about 3 a.m.) and then block out bright light (such as the rising sun) on their way home to sleep. Wear sunglasses or goggles to achieve this, and create a totally dark, quiet sleep environment at home.

Our modern world is so well-lit that it might seem hard to dim the lights in preparation for sleep and then seek near-total darkness for sleep. But according to emerging research, your best bet for healthy sleep is to do just that.

Darkness Matters – How Light Affects Sleep

Light has a profound effect on sleep. Exposure to light early in the day stimulates the body and mind, encouraging feelings of wakefulness, alertness, and energy. Light exposure at night also stimulates alertness—and that can pose a serious problem for healthy, abundant, refreshing sleep. Light exposure during the evening can make it harder to fall asleep. Insufficient darkness throughout the night can lead to frequent and prolonged awakenings.

How darkness influences sleep

Darkness is essential to sleep. The absence of light sends a critical signal to the body that it is time to rest. Light exposure at the wrong times alters the body’s internal “sleep clock”—the biological mechanism that regulates sleep-wake cycles—in ways that interfere with both the quantity and quality of sleep. Melatonin, a hormone produced in the brain’s pineal glad, is often known as the “sleep hormone” or the “darkness hormone.” Melatonin influences sleep by sending a signal to the brain that it is time for rest. This signal helps initiate the body’s physiological preparations for sleep—muscles begin to relax, feelings of drowsiness increase, body temperature drops. Melatonin levels naturally rise during the early evening as darkness falls and continue to climb throughout most of the night, before peaking at approximately 3 a.m. Levels of melatonin then fall during the early morning and remain low during much of the day. Evening light exposure inhibits the naturally timed rise of melatonin, which delays the onset of the body’s transition to sleep and sleep itself.

Light as a modern sleep problem

For most of history, humans did not need to seek out darkness. The advent of electricity in the 20th century fundamentally changed our relationship to light and dark, and posed serious new challenges to sleep. Artificial light, inexpensive and ever-present, wreaks frequent havoc on sleep without many people even being aware of its detrimental effects. The widespread use of digital technology—and the light emitted from all those screens—has introduced another highly disruptive challenge to sleep.

Measuring light: lux and lumen

Understanding how light is measured can help you manage your exposure to light more thoughtfully, and with an eye toward improving your sleep. There are a couple of measurements that are important in the world of light and dark: lumen and lux. Lumen is a measurement of light intensity or brightness, also known as radiance, at the source of the light itself. As light moves from its source, it disperses and its intensity changes. So when we’re thinking about our exposure to light, it’s not just the intensity of light itself that matters, it’s also our distance from the light. That’s where lux comes in. Lux takes lumen values and factors in the surface area over which light spreads. Lumen values can tell you how bright a light bulb is, but lux values can give an indication of how bright that light is in the space in which it—and you—reside. Lux measurements are also commonly referred to as “incident light.”

Using lux, indoors and out

Lux can be used to measure all types of light, both natural light and artificial light, and these values can vary tremendously depending on both the source of light, its power, and its proximity. Here’s a little perspective on lux: On a sunny summer day, your environment might be in the range of 150,000 lux. Now imagine a cloudy winter day, when the sun is farther from you and obscured: a typical lux measurement on a day like that might be as low as 1,000. At night when darkness falls, lux values plummet. The moon generates values under a single lux.

A typically-lit home, with lamplight and overhead light, as well as light from outside, may have lux readings in the range of 300-500. The lux values of your environment at night will influence how easily your body prepares for sleep. In the evening hours, it’s important to maintain low lighting, and allow your body to undergo its natural physiological move toward sleep. Appropriate lux for pre-bedtime activities in the evening, like reading, should be less than 180 lux. This level of brightness will allow you to be quietly active but won’t impede your body’s progress toward sleep. After light’s out, your bedroom should be dark, with lux no higher than 5.

Make light right for sleep

Managing your exposure to light in your home and in your bedroom is fundamental to creating a healthy sleep environment. With awareness, attention, and some simple planning, you can create a bedroom that guards against unwanted light at night, and protects the quality of your sleep until you are ready to wake. Curtains and shades on windows keep outside light from disturbing your sleep. Make sure window coverings are heavy enough to fully block light, and are well fitted to avoid slivers of streetlight or early morning sunlight from filtering in. Even brief exposure to light can interfere with sleep. Blackout curtains are designed to provide this kind of thorough protection against unwanted light.

Nightlights can help

If you need a source of light during the night—to make your way comfortably to the bathroom or to a child’s bedroom—use a nightlight with a red bulb. Red is a long wavelength light that has been shown less disruptive to sleep than other light wavelengths. Put the nightlight in a hallway or another room, if possible. Having a small light in place will help you avoid having to flood your middle-of-night environment with unwanted, sleep-disrupting brightness.

Ways to create darkness

The body needs time to prepare for sleep. A sleep routine that includes a gradually darkening environment can help. Dim the lights a full hour before bedtime to encourage your body to begin its physiological progression toward sleep. Use a dimmer switch on overhead lights to control their brightness, or install low-watt, dimmable bulbs in lamps. Avoid screen time the hour before bed: turn off the television, power down computers and tablets, and put your phone away for the night. The light from digital devices contains high concentrations of blue light, a wavelength of light that research has shown is especially detrimental to sleep.

An eye mask worn at night can help deepen darkness and protect against intrusive light. Choose a mask that is soft, comfortable, and flexible. Wearing an eye mask can take a little getting used to, but it is a highly effective tool for limiting your light exposure at night.

Being aware of light’s effects on the body will lead you to pay more attention to the light that surrounds you, both day and night. Taking a little time to ensure a dark sleeping environment is one easy and important way to protect and improve your nightly rest.


Sleeping is the time for our body to rest and recuperate. Adults usually need seven to eight hours of sleep, while children and teenagers need less than 10 hours.

To make sure we benefit the most from our time in the land of nod, it is important to do it right, including whether to turn off the light or leave it on all night, as reported by

Connection to cancer

The National Center for Biology Information (NCBI) in the United States found that sleeping with the light on may shorten melatonin duration by about 90 minutes. Exposure to artificial light during normal sleeping hours may also suppress melatonin by 50 percent. Melatonin is a hormone that regulates sleep and wakefulness.

Leaving the lights on may even lead to sickness, including cancer. A study showed that women who sleep under higher intensity light have a higher chance of developing breast cancer than those who sleep with the lights off, as quoted by Gizmodo. Melatonin suppression is said to be the cause.

Read also: Night owls risk dying younger, should sleep in: Study

Weight gain

A research published in the International Journal of Obesity showed that artificial light makes people gain weight, and the effects are similar to eating junk food, as reported by Reuters. This is because the light is able to disrupt your sleep schedule and quality as well as disrupting your eating habits.


Getting exposed to light for too long, either in your bedroom, office or from your smartphone screen, will affect your stress hormone, cortisol, and is also connected to your mental health. The Huffington Post reported a study published in Nature journal that experimented on mice. The result revealed that the mice showed behaviors indicative of depression, such as moving less than usual and having an impaired memory. (wir/wng)

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How many times have you fallen asleep with the lights, or television on, or even stayed up late to use your computer right before going to bed?

A key factor in regulating sleep and your biological clocks is exposure to light or to darkness so falling asleep with lights on may not be the best thing for a good night’s sleep.

Exposure to light stimulates a nerve pathway from the eye to parts of the brain that control hormones, body temperature and other functions that play a role in making us feel sleepy or wide-awake.

Too much light, right before bedtime may prevent you from getting a good night’s sleep. In fact, one study recently found that exposure to unnatural light cycles may have real consequences for our health including increased risk for depression. Regulating exposure to light is an effective way to keep circadian rhythms in check.

  • During the day, find time for sunlight, or purchase a light-box or light visor to supplement your exposure to light.
  • At night, keep your sleep environment dark. Light-blocking curtains, drapes or an eye mask can also help, and if you find yourself waking up in the middle of the night, avoid as much light as possible by using a low illumination night light. F
  • or shift workers, who need get their zzz’s during the day wearing dark glasses to block out the sunlight on the way home from work is another way to limit light before bedtime. Some research indicates that the body may never fully adapt to shift work, especially for those who switch to a normal weekend sleep schedule. Establish a routine for sleep to avoid dozing with the television or lights on.
  • Before bedtime, limit television viewing and computer use, especially in the bedroom, as they hinder quality sleep.

Setting good sleep habits is particularly important for infants and children, as it directly impacts mental and physical development. Circadian rhythms develop at about six weeks, and by three to six months, most infants have a regular sleep-wake cycle. Learning to work with your body is essential for good health, because every living creature needs sleep.

Discover the 5 benefits of sleeping in the dark!

Some people prefer sleeping in total darkness, and some just can’t close their eyes if they don’t have a bedside lamp or a night light turned on.

Falling asleep with a dim night light might appear relaxing, but actually, these seemingly harmless lights can prevent your healthy sleep. Discover the 5 benefits of sleeping in complete darkness.

1. Complete darkness makes it easier to fall asleep

As you prepare to go to bed, turn off all the brighter lights, and keep a subtle bedside light on. Darkness promotes relaxation and stimulates the production of melatonin, the hormone that helps us fall asleep more easily.

However, once you are in bed, it is advisable to switch off any light. Even while we sleep, our brain detects light through the eyelids and is no longer able to produce melatonin as it confuses night and day.

2. Sleeping in the darkness dispels depression

According to research conducted at Ohio State University Hospital, sleeping near a light source disturbs the circadian rhythm. In other words, our body doesn’t know what time to go to bed, and our body rhythm is distorted, causing mental imbalance, and the possible consequent risk of suffering from depression.

3. Sleeping in the dark keeps you fit!

Several studies have shown that sleeping with a light on could increase body weight by 50% (although dieticians and nutritionists never recommend it). This happens because light alters the body’s biological rhythms and metabolic parameters.

Find out in our article how night rest affects your physical condition!

4. Sleeping in the darkness offers relief to the eyes

Sleeping in the dark helps your eyes rest properly and protects them. Not surprisingly, children who usually sleep with a light on are the ones that experience more myopia issues.

Furthermore, establishing good resting habits is particularly important for infants and children as they directly influence mental and physical development. Find out more in our article!

5. Sleeping in the dark reduces the chance of diabetes

A new study conducted at the Northwestern University Feinberg School of Medicine in Chicago and published in the scientific journal Sleep, reveals that having a light on during sleep can have a negative impact on diabetes.

In fact, it has emerged that exposure to light during sleep hours can affect insulin resistance.

Our tips for healthy sleep

Although we usually associate darkness with nightmares, total darkness in the bedroom is the secret for a good rest.

However, remember to choose a quality bed system able to satisfy your physical characteristics and sleeping habits!

Written by Manifattura Falomo – Marketing Office

To Control Light For Better Sleep

Darkness is needed for a good night’s sleep. And the more darkness, the better. If you are having trouble sleeping and your bedroom is not totally dark when you try to sleep, you should take steps to eliminate or, at least, reduce the light.

Sleeping in complete darkness is important to getting a good night’s sleep because darkness or night increases the production of melatonin. Melatonin is a hormone produced by the pineal gland in the brain and controls the body’s sleeping cycle. Melatonin is believed to cause a person to fall asleep faster and sleep better.

If you are exposed to light while you are trying to sleep, melatonin may not rise to high enough levels to do its job. Light coming in from the window, light entering from another room, or even a night light can disrupt the production of melatonin. In other words, if you want the best opportunity to fall asleep quickly and sleep soundly, you must have darkness.

A lack of darkness at night has even been linked to an increased risk in cancer for women.

Four Ways To Achieve Darkness For Sleep

  • Sleep Masks
    They are inexpensive, generally effective and portable.
  • Light-Blocking Window Treatment
    There are many effective options to choose from.
  • Dark Surfaces
    Learn why a bedroom with bright colors can be the enemy of sleep.
  • Motion-sensing Nightlights
    A sleep-friendly nightlight is one that only comes on when you need it.

Should I Use a Nightlight?

A look inside whether the glow has to go

It seems pretty obvious: If you want to be able to see in your bedroom at night, plug in a dim nightlight to cut through the darkness. But even though a nightlight will help guide you on your nighttime trips to the bathroom, it can cost you. Having a nightlight in your room will disturb natural melatonin production. Why does that matter? Melatonin is a hormone that promotes sleep. And even with your eyelids closed, the light is detected and your brain gets confused about what time it is. As a result, your body doesn’t produce as much melatonin. This doesn’t just impair your sleep. Being exposed to light throughout the night impacts hormone function and is connected to depression and an increased cancer risk. For all of those reasons, keeping your room as dark as possible really is best.

If all that isn’t enough to deter you and you still want to have a nightlight, keep this in mind: Just like different styles of bulbs can be better for your home, different colored bulbs can have a different impact on your body. Blue lights are the worst for your mood (and white lights aren’t far behind), but red bulbs are a different story. It turns out that red lights don’t have the same negative effects on your health as white lights do. While they also aren’t as common as white bulbs, you can find them on or at hardware stores. Another option: Place the night light in the bathroom (where you will likely be heading when walking around at 3:00am). That way, your eyes won’t sense it all night long, so your melatonin will stay at optimal levels, but you will still avoid stubbing your toe on the toilet.

Now, if you’re wondering whether or not you should have a nightlight on in your baby’s nursery, the answer is that it’s up to you. You might feel more comfortable having one on in there. Maybe the little bit of light makes your baby calmer or less anxious. Or maybe you like that it’s easier for you to sneak in and check on the baby with the nightlight on without disturbing him or her. If that’s the case, feel free to plug one in—it isn’t going to have a huge impact on your baby’s ability to sleep well at night. But keep in mind that not all babies are instinctively afraid of the dark. Think of it this way: Your baby spent a long time in a pretty dark environment (a womb), so it isn’t a given that there will be a freak out if he or she wakes up and it’s dark in the bedroom.

Is your heart rate spiking while you sleep?

Are you one of the many people who fall asleep in front of the tv, sleep with the lights on, or work l in front of your computer screen right up until your bedtime? If so, you are putting yourself at risk for a night (or nights!) of unhealthy sleep.

Both lightness and darkness impact our sleep. Exposure to light early in the day stimulates our body and our mind, making us feel awake, alert, and energized. Yet exposure to light at night also stimulates alertness that can hinder us getting a restful night of sleep.

How sleeping with the lights on affects your sleep

Your exposure to light or darkness is a key factor in the regulation of sleep so falling asleep with the lights on may not be the best thing for a good night’s sleep. Artificial light, whether from lights or lamps, phone, computer screens, or the TV, disrupts the body’s circadian rhythm, our body’s 24-hour sleep/wake cycle. Sleeping with the lights on has an effect on your brain wave patterns, the natural cycle of Melatonin production, and cell regulation all which disrupt your sleep cycle. This has been linked to a variety of health issues like depression, obesity, breast and prostate cancer, and cardiovascular disease, to name a few. It’s also associated with sleep disorders like insomnia. Therefore, regulating your exposure to light is an effective way to keep circadian rhythms in check and benefit your health.

How melatonin affects our sleep

Melatonin influences sleep by sending a signal to the brain that it is time for rest. This signal helps initiate the body’s physiological preparations for sleep—our muscles start to relax, we begin to feel drowsy, and our body temperature drops. Melatonin levels naturally rise during the early evening as darkness falls and continue to climb throughout most of the night, before peaking at approximately 3 a.m. Melatonin levels then fall during the early morning and remain low during much of the day. Evening light exposure inhibits the naturally timed rise of melatonin, which delays the onset of the body’s transition to sleep.

What about when you’re actually sleeping? “As long as … you get those flashes of light, it’s getting through your eyelid,” Donald Greenblatt, M.D., director of the University of Rochester Medicine Sleep Center, tells SELF. Your eyelids are made of a thin enough material that this can definitely put you at risk of suppressing the melatonin secretion you need to sleep soundly, Dr. Greenblatt explains. You could also wake up due to the flashes of light themselves. However, your proximity to your screen can definitely have an impact here. “You’re probably getting less exposure to light from a TV that’s across the room rather than a tablet that’s in front of your face,” Dr. Greenblatt says.

How sounds from your TV affect your sleep

We’ve established that a flickering screen right in front of your face may affect your sleep, but there’s also the matter of sound.

“Some people would argue that something like TV in the background may be helpful because it prevents you from starting to ruminate or think about things that will get you into a pattern of what we call psychophysiological insomnia, where you’re not able to relax enough to fall asleep,” Dr. Greenblatt says. “There’s some element of truth in that, but the flipside is that the ambient noise of television is not steady.” Soothing and steady ambient sounds, like white noise or even a purring cat, can help some people fall and stay asleep, but the sporadic nature of TV noise could mess with your rest.

Environmental noise—like your neighbor stomping across her floor or a randomly loud-as-hell TV commercial—can interrupt your sleep without you even remembering it.

What all this means for your sleep quality

The primary concern here is that TV light and sound will keep you from getting into the deeper, more restorative stages of sleep, Dr. Augelli says. This can result in sleep deprivation, which can cause daytime sleepiness, irritation, lack of focus, and even muscle aches, according to the Mayo Clinic.

There’s also a possibility that this could affect your dreams. While there isn’t a lot of evidence to indicate that sleeping with the TV will give you Game of Thrones-themed nightmares, it’s possible that, say, a noise on the TV wakes you, you catch a glimpse of an adorable dog on the screen, and next thing you know you’re dreaming about rolling around in a pile of puppies. (Sign us up.)
But even if you don’t fully wake up, your brain is still active when you sleep, Dr. Augelli says. “We’re less attuned, but we’re not completely unaware, so you just don’t want to have a lot of sensory input,” she explains. And, of course, if you drift off to something disturbing, it could influence the contents of your dreams, Dr. Greenblatt says.

But what if you’re someone who always sleeps with the TV on and feels pretty damn rested when they wake up? “Sometimes we can get away with something until we can’t,” Dr. Augelli says. Ultimately, even if you have the TV on mute, the light can impact your circadian rhythm, Dr. Augelli explains. This might not impact your sleep in a major enough way for you to feel it the next day. But, as SELF previously reported, your circadian rhythm influences a lot more than just your rest. That includes your metabolism, hormone fluctuations, and even your body temperature—all pretty important processes that you don’t want light to potentially mess with.

What to do instead

Listen, if you always fall asleep with the TV on and feel well-rested, we can’t force you to stop. If, however, you suspect it might be messing with your sleep, it could be time to consider putting an end to this habit. There’s a reason why going to bed in a dark, quiet room is a cornerstone of great sleep hygiene.

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