The Dark Side Of Light At Night

The Dark Side of Light at Night

Even more so than diet and exercise our quality of sleep is the single best predictor of longevity! It's vital for hormonal balance, maintenance of optimal body weight, immunity, cognitive function and mood. When sleep is compromised our risk of blood clots, stroke, cardiovascular disease, diabetes, autoimmune disorders obesity, inflammation and cancer are all increased (1,2).

Getting adequate high-quality sleep is one of the most crucial yet often neglected things we can do to improve our overall health and vitality. That being said however, as many as one quarter of all New Zealanders report suffering from chronic sleep problems and 45% said they experienced insomnia at least once per week (3). What's causing this epidemic of sleep problems in our country?

While there are many possible causes of sleep disturbance, from hormonal fluctuations to nutrient deficiencies, I want to focus on one that affects us unanimously - the use of electronics and light at night. Checking your email or text messages, watching TV and the light in your bedroom may seem harmless, but these can all profoundly and negatively impact our health through suppressing the hormone melatonin.

While the blue light from devices is notorious for reducing melatonin levels, newer research shows that even one hour of light exposure at 500 lux (such as a bright office or supermarket), can suppress melatonin by more than 50% (4). Melatonin is derived from the neurotransmitter serotonin - the little brain chemical made famous by SSRI antidepressant medications like Prozac (fluoxetine) and Celexa (citalopram). It is made by the pineal gland in the brain in response to fading daytime light and helps to set the body's sleep and wake cycle.  In order to activate melatonin's release at night though we need to be exposed to sunlight during the day.

Melatonin suppression is not only bad news for sleep, but research shows that melatonin also plays an important role in immune function and that when suppressed increases our risk of various cancers (especially breast and prostate cancer) (5,6).  In fact in my integrative medical practice we often administer melatonin to help down regulate estrogen receptors in some breast cancer patients and use it as an adjunctive treatment in some solid tumors, as it has been shown to have an anti-proliferative effect on cancer cells (7,8).  Finally light at night and melatonin suppression have been linked to increased risk of diabetes and cardiovascular disease - still the number one killer of men and women in the developed world.

Melatonin tells your body and brain its time for rest, sets up the circadian release of other hormones and regulates the menstrual cycle in women while also protecting immune function and acting as a strong antioxidant in the body (9).  I love my iPhone as much as anyone else, and detest stubbing my toes on the dresser when trying to navigate my bedroom in the dark, so what can we do to protect our melatonin levels without giving up the luxuries of modern life?

1. Blue blocking glasses. Special glasses with lenses that reduce the amount of blue light reaching your eyes are probably the easiest and most important intervention. Studies show that blue light blocking glasses are extremely effective at stopping the melatonin suppression causes by blue wavelengths of light.  Check out for many styles. They should have yellow or amber lenses, and have 80-90% filtering rate.  Put them on 3 hours before bedtime for best effects (10).

2. Night Shift and Flux. Night vision is found in iPhone settings, under "display and brightness". I leave mine on all the time, although it does impact battery life. Use it at least 3 hours before bed. F.lux can be downloaded here for your android device or computer. Both essentially change the type of light emitted from screens, removing a portion of the blue light that most strongly suppresses melatonin.
Blue light removing screen protectors. Another option for devices are blue light filtering screen protectors. I use Zen Tech

3. Sunlight in the morning and during the day. As mentioned before sun exposure is essential to help set your circadian rhythm. Without full spectrum light during the day you won't make melatonin to be released when that light goes away. I find that advising patients to sit outside in the morning sun while they drink their coffee (face the direction of the sun but do not look directly at it) is one of the best interventions for insomnia. Ideally aim for two hours of sunlight per day for optimal health.

4. Candles, low wattage orange or red light bulbs. Replace bedroom and reading lights with these options that have been shown not to affect melatonin as much as regular light bulbs. Check out this table on light intensity.  Remember 1000lux for one hour or 500lux for two hours in the evening is enough to suppress melatonin to day time levels, compare your light environment with the examples on the chart. You can find amber bulbs at most hardware stores.
Make sure you sleep in complete darkness. When you get into bed hold your hand up in front of your face.  If you can see it, your room is too bright for optimal sleep and melatonin release. Consider installing black out blinds or using a sleep mask.
Avoid watching TV before bed. TV's emit blue light that suppress melatonin. Try to avoid TV after 9pm.

5. Be mindful of electromagnetic fields produced by electronic devices such as alarm clocks and cell phones set to charge on your bed stand.  Always put your phone into airplane mode and keep all electronics at least three feet away from your head when you sleep.  Ideally turn your Wi-Fi router off at night. Research suggests that certain electromagnetic fields may interfere with pineal melatonin production (11).

6. Supplement with melatonin precursors. Taking the amino acid L-Tryptophan or its metabolite 5-HTP can help augment serotonin and thus melatonin levels. The vitamin B6 is also required to feed this pathway.  Talk to your doctor before supplementing with over the counter products, but for most people taking 50-100mg of 5-HTP, or 500mg of L-Tryptophan is safe and can be very effective at increasing serotonin and therefore melatonin (12).  DO NOT take serotonin precursors if you take antidepressant medications.

7. Watch your Cortisol. Cortisol is a stress hormone secreted by the adrenal glands.  If it is high at bedtime it will interfere with melatonin and nighttime growth hormone secretion.  If you are stressed, can't sleep and have trouble unwinding at night this could mean your cortisol is too high in the latter parts of the day.  Cortisol can be measured via a salivary sample taken 4-5 times throughout the day and before bed. It should peak in the early morning hours stimulating you to wake up and dip down at night to allow for restful sleep.

8. If you suspect melatonin abnormalities, excess stress or cortisol are contributing to your sleep problems or affecting your health, talk to your doctor or feel free to reach out to us at Bloom

Sweet dreams!

Dr. Vanessa Ingraham, NMD, ABAAHP
Naturopathic Medical Doctor
Fellow in Anti-aging, Regenerative and Functional medicine














Vanessa Ingraham