February 24, 2015

Improve your Sleep through the Daily Balance of Light & Darkness.

Pablo Miranzo/Flickr

Sleep is a crucial element of optimal wellbeing.

You could have the ideal lifestyle with respect to the food you’re eating, the water you’re drinking, and exercise, but if you don’t sleep well, you’re just not going to be optimally healthy.

Here I want to talk about the most natural and often neglected solution to optimal sleep—the balance of light and darkness throughout the day.

The problem we have as a society is that we’re not getting enough bright light exposure during the day, and then in the evening, we’re getting too much artificial light exposure. Both of these have the consequence of causing our natural body rhythms to get out of sync.

Maintaining a natural rhythm of exposure to daylight during the day, and darkness at night, is an essential component of sleeping well. The reason why light is important is because it serves as the major synchronizer of your body’s master clock.

This master clock is a group of cells in your brain called the suprachiasmatic nuclei (SCN). As a group, these nuclei synchronize to the light-dark cycle of your environment and control the production of melatonin, a hormone that makes you sleepy. Since SCN is located just above the optic nerves, which relay information from the eyes to the brain, the SCN receives information about incoming light. When there is less light—like at night—the SCN tells the brain to make more melatonin so you get drowsy.

You can help your body’s natural rhythms to stay in sync by following 4 simple rules:

1. Every day spend at least 30 minutes outside in the bright light.

Most of us don’t have the luxury to spend the whole days outside like the nature intended. However, 30-60 minutes of bright daily light is all it takes for your body’s master clock to get the message. Ideally, you should try to be outside around noon as the sun is the brightest during that time. Going for walk during the lunch time is a great idea.

2. Eliminate blue light from computers and other electronic devices in the evening.

Research shows that computers, TV screens, iPads and other electronic devices emit light that causes melatonin suppression. If used before going to bed, they negatively affect your sleep, circadian timing, and next-morning alertness. However, it’s not all the emitted light that is so detrimental to your sleep. The main culprit is the blue light, because its specific wavelengths have a strong melatonin suppressing effect. While it would be best to avoid all electronic media during the last hour before going to bed, an alternative solution would be to use blue light blocking in the form of screen shields (SleepShield or similar) or a computer program, such as f.lux, for example.

3. Dim the lights in your house or use the candle light one hour before going to bed.

TVs and computers are not the only sources of light that can suppress melatonin. Bright house lights have a similar effect. Try dimming all the lights in the house or, even better, using a candle light during the last hour before bed and notice how much more sleepy and relaxed you will feel.

4. Keep your bedroom totally dark.

To improve the quality of sleep and circadian timing, it’s important to keep the bedroom totally dark. Even the small amount of street light can negatively affect sleep, especially in sensitive people. Put special light-blocking curtains on the windows or wear a sleeping mask. In addition to blocking the light, light pressure on the eyes from a sleeping mask tends to have a calming effect on most people. I find Dream Silk the most convenient and effective.

Keeping the balance between light and darkness can have a profound effect on your sleep and quality of life. Try it for several days and share your experience in the comments!





Effect of Light on Human Circadian Physiology.  Jeanne F. Duffy, Charles A. Czeisler. Sleep Med Clin. 2009 June; 4(2): 165–177.

Insufficient sleep undermines dietary efforts to reduce adiposity. Arlet V. Nedeltcheva, et al. Ann Intern Med. 2010 Oct 5; 153(7): 435–441.

National Sleep Foundation: How Light Affects Sleep

Evening use of light-emitting eReaders negatively affects sleep, circadian timing, and next-morning alertness. Anne-Marie Chang, et al. PNAS, vol. 112, no. 4: 1232–1237.

Exposure to Room Light before Bedtime Suppresses Melatonin Onset and Shortens Melatonin Duration in Humans. Joshua J. Gooley, et al. Clin Endocrinol Metab. 2011 March; 96(3): E463–E472.

The human circadian system adapts to prior photic history. Anne-Marie Chang, et al.  J Physiol. 2011 March 1; 589(Pt 5): 1095–1102.

Prevention and treatment of sleep disorders through regulation of sleeping habits. Onen SH, et al. Presse Med.1994; Mar 12; 23(10): 485-9.



Author: Natalia Lukina

Editor: Emily Bartran

Photo: Pablo Miranzo/Flickr

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