Is Night Lighting Making You Fat, Tired & Depressed?

Posted On Wednesday, 15 October 2014
Is Night Lighting Making You Fat, Tired & Depressed?
Dr. Holly welcomes health coach, Sarah Corey, as a guest blogger this week. For more from Sarah and Dr. Holly on this topic, listen to their conversation about Struggling to Sleep: Is there Too Much Light in Your Bedroom?

Now, here's Sarah:

We all know that getting a good night sleep is an important part of a healthy lifestyle. Studies continuously show that achieving 7-9 hours of restful sleep nightly can have many health benefits including reduced the risk of chronic diseases, stress relief, improved cognitive function, weight control and even weight loss.

In our every connected digital age many of us are being exposed to light by our devices right up until the moment we get into bed, and for many of us, we even take these devices in bed! All light can disturb our sleep, however the light omitting from laptops, iphones and ipads is blue wave light, a wavelength that can be most destructive to our sleep cycle. This light inhibits our pineal gland from releasing a hormone called melatonin, which helps reduce alertness and put you to sleep. At a very basic level melatonin production is stimulated by darkness and inhibited by light.

While light affects our sleep and health in many ways, there are four main ways that this lack of sleep may be affected our bodies:

1. Depression: A study in the 2013 Journal of Affective Disorders has shown that people who suffer from depression have higher levels of nighttime light in their bedrooms. We all know that when we don't get enough sleep we can become irritable, anxious and depressed. Why might this be? It goes back to melatonin. Melatonin can actually be a natural mood booster and the lack of proper production can make you feel blue.

2. Obesity: A study posted in the American Journal of epidemiology found that women sleeping in brighter rooms had higher BMI and larger waist sizes than those who slept in dark rooms. This study also found that even slight amounts of light could alter your production of melatonin. If you're like me I always notice that when I don't sleep I crave carbohydrates. Like we spoke about before this goes back to melatonin production. Changes in melatonin production can have impact other hormones such as leptin, the satiety hormone that regulates the amount of fat stored in the body by adjusting the sensation of hunger, which of course is involved in hunger and appetite regulation. Having the proper amount of sleep is one of the most important factors in controlling leptin levels. It is secreted at its highest during the evening and those who did not have enough sleep showed leptin peaks earlier which disturbed their hormonal balance and encouraged weight gain.

3. Diabetes Mellitus Type II: An April 2014 study found that many patients with diabetes had higher exposure levels to light four hours prior to sleep. As the amount of light they were exposed to doubled the rate of diabetes increased by over 50%! Again this goes back to melatonin, which as we discussed plays a role in both leptin and glucose control. Low levels of melatonin have been showed to be linked to high risk of Type II diabetes.

4. Insomnia: Beyond being depressed, overweight, and diabetic people who are exposed to bright light also suffer from poor sleep quality and lack of sleep. Low melatonin will decrease your ability to stay asleep. This is very important for those of you who wake up in the middle of the night and check your iphones or your laptops. Just this little exposure to light can interfere with your sleep cycle and further reduce your chance of getting a good nights rest.

Having a good sleep hygiene program is essential to health. Try to incorporate one or all of these tips below this week and see how much better you can feel when you get your sleep cycle under control.

1. Create a routine that relaxes both body and mind and prepares you to go to sleep. Read a book, take a bath, journal or do some relaxing yoga poses. You can easily good "restorative yoga poses" and find photos online to print out and follow along to, or watch a video earlier in the day and try those poses again before bed. Do this nightly and start to program your body to wind down and prepare for bed.

2. Turn off all devices including TV, computer, and i-phone at least 1 hour before bed.

3. Install the f.lux app, or one similar, onto your computer, ipad, iphones which will help reduce blue light exposure at night. This app adjusts the light based on the time of day which can help significantly with your melatonin levels at night when using these devices. You can find it at

4. Cover any lights that stay lite in your bedroom, or sleep with a light blocking eye mask to avoid any additional light.

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