Get More Sun – Why Indoor Light is Ruining Your Sleep

Do you feel groggy in the mornings but still struggle to fall asleep at bedtime? Do you often have trouble sleeping through the night and then suffer for it the next day? Since the advent of electricity, scientists have studied the effects of light on sleep. Electric lights — particularly the blue light emitted by computers and other electronics — interfere with the chemicals that regulate our circadian rhythms or sleep cycles. Anyone who has worked a night shift or flown across time zones can attest to this. Long after the sun has set, these lights trick the brain into thinking it’s still daylight. Happily, new evidence suggests it doesn’t take long to reset misaligned sleep cycles.

Resetting Your Sleep Cycle

Sleep scientist Kenneth Wright and his colleagues at the Sleep and Chronobiology Institute at the University of Colorado at Boulder[note]Kenneth Wright, Andrew W. McHill, Brian R. Birks, Brandon R. Griffin, Thomas Rusterholz, Evan D. Chinoy (2013, 19 August). “Entrainment of the Human Circadian Clock to the Natural Light-Dark Cycle.” Current Biology 23 (16): R689-R690. Retrieved from http://www.cell.com/current-biology/abstract/S0960-9822(13)00764-1[/note] sent eight test subjects packing for seven days in the woods away from all other artificial light sources. The campers went about their business and slept when they chose, all while wearing special devices to monitor their sleep patterns and melatonin levels — one of the primary chemicals responsible for triggering sleep in humans and other animals.

After just one week, the campers returned to the lab for assessment. Each camper’s data was compared to pre-experiment data taken during a week of normal activity. Across the board, researchers noted an increased melatonin production at nightfall and lower levels of melatonin during the day, helping the subjects sleep better at night and be more alert in the morning. Self-proclaimed night owls saw the most dramatic shift, going to sleep an average of two hours earlier and waking an average of two hours earlier as well. Exposed to nothing but natural light, the campers’ sleep cycles reset to the natural light-dark cycle of daylight hours.

Costs of Sleep Deprivation

According to the Center for Disease Control and Prevention[note]“Insufficient Sleep Is a Public Health Epidemic.” National Center for Chronic Disease and Prevention and Health Promotion, Division of Adult and Community Health. Retrieved from http://www.cdc.gov/features/dssleep/index.html[/note], at least one third of Americans suffer from chronic sleep insufficiency. Lack of sleep can lead to a plethora of other health issues, including hypertension, diabetes, depression, and obesity[note] Institute of Medicine (2006), Sleep Disorders and Sleep Deprivation: An Unmet Public Health Problem. Washington, DC: The National Academies Press[/note]. Additionally, less than optimal sleep increases rates of cancer and even death. In one study overseen by the American Association for Cancer Research, melatonin suppression caused by nighttime light exposure in rats made malignant tumors more resistant to the breast cancer treatment tamoxifen. In the experiment, rats kept in dim light throughout the night —  comparable to the light that leaks into a bedroom window at night — had a 2.6-fold increase in the rate of tumor growth when compared to those who were kept in twelve hours of complete darkness[note]“Exposure to Dim Light at Night May Make Breast Cancers Resistant to Tamoxifen” (2014, July 25). American Association for Cancer Research. Retrieved from http://www.aacr.org/Newsroom/Pages/News-Release-Detail.aspx?ItemID=569[/note]. Even in less extreme cases, sleeplessness impacts our ability to concentrate, our resilience in stressful situations, and our regulation of moods.

With modern lifestyles revolving around dimly lit offices and late night email, it’s no wonder our brains have trouble gauging when to cue sleep and when to be most alert. The good news is you don’t have to go trekking into the woods every time you want a good night’s rest. Using the findings of Wright’s study and others, you can make a few practical changes to help offset the most glaring effects of light interference and improve the duration and the quality of your sleep.

Beating the Blues

Not all light affects the brain in the same way. For reasons yet unclear, blue light seems to have the strongest impact on melatonin production. Blue light is found in sunlight but also in artificial light sources, from small quantities in iridescent lights to larger quantities in curlicue compact fluorescent light bulbs and LEDs. The most common contributors in our modern world, however, are the monitors on our computers and televisions. According to Harvard researchers, blue light’s effects can elevate attentiveness and even mood, which is great in the morning but not so helpful as we’re preparing for bed[note]“Blue Light Has a Dark Side” (2012, May 1). Harvard Health Publications. Retrieved from http://www.health.harvard.edu/staying-healthy/blue-light-has-a-dark-side[/note]. After sunset and as we draw closer to sleep, even light from street lights or cars can have a negative impact on our readiness for sleep, and mini-blinds and light curtains are not enough to keep it at bay.

So what’s to be done? Avoiding the use of electronics after dark would certainly be an effective approach, but it’s not always practical. A team at the Lighting Research Center at the Rensselaer Polytechnic Institute has studied the benefit of blue-light blocking goggles on a group of college students while using their laptops[note]MG Figuero, B Wood, B Plitnick, MS Rea (2011). “The Impact of Light from Computer Monitors on Melatonin Levels in College Students.” Neuroendocrinology Letters 32(2):158-63. Retrieved from http://www.ncbi.nlm.nih.gov/pubmed/21552190[/note]. The goggles’ effectiveness at mitigating the melatonin-blocking effects of blue light looks promising but inconclusive. A more cost effective option might be software that adds a warm filter to your computer screen at night to help block the offending blue light, though the effects of these programs have not been studied in detail. In the meantime, practice good sleep hygiene and close your laptop and dim the lights at least a half an hour before bed. And if light travels in from outside, consider investing in a set of blackout curtains for the bedroom or a sleep mask.

Daily Dose of Sunlight

Just as important as avoiding unwanted light at night, upping your exposure to daytime sunlight can make a huge difference in getting your sleep schedule back on track. Looking back at the group of campers in Wright’s experiment, it’s clear that time outside in natural sunlight was part of the winning formula. Incorporating this principle into your own life can be as simple as taking a short walk during your lunch break or opening the blinds next to your workspace. Sunlight can be especially powerful earlier in the day when we’re still priming our bodies to slow down on melatonin production and shift into wakefulness. Some find the use of artificial sunlight lamps, particularly during the dark winter months, to be helpful as part of their early morning routine.

Whatever your approach, timely light exposure — increasing time outdoors during the day and cutting back on the use of artificial lights at night — can have a major impact on combatting sleeplessness and making you feel more fully rested.

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Featured Image is Blaze Of Glory – Syon House & Park, The Great Conservatory – London by Simon & His Camera. CC BY-ND 4.0

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