“Let There Be Light”
Heather Johnson, RN, Resource Nurse
Light exposure does play a significant role as it helps this internal clock regulate our sleep and waking schedules
Have you ever wondered why light exposure plays such a significant role in setting our internal clock?
With the invention of the electric light bulb in the late 19th century, our bodies started to be exposed to more light than humans had ever been exposed to before. Because of this, our patterns of sleep are negatively impacted.
Most living creatures, including humans, have a similar internal clock, also known as the circadian rhythm. Humans, as diurnal creatures, have evolved to sleep at night and active during the day light hours. Deep within our brain there is an area called the hypothalamus which regulates the functions of our body, including sleep, energy, and hunger. Without the right amount of light exposure our bodies would have a very difficult time, at best, to regulate our sleep and wake cycles.
The natural way our circadian rhythm works is that rays of sunlight hit the cells in the retina of our eyes, the light triggers the release of the hormone serotonin (the “happy-feel good” hormone). Serotonin, which is mostly stored in our gut, is released. As the sunlight goes down in the evening and exposure to sunlight and environmental light decreases, our bodies are cued to start producing Melatonin. The hormone Melatonin “drives” our bodies for sleep at night. Since the invention of the light bulb our prolonged exposure to light late in the evening delays our body’s ability to sleep and messes up our internal clock.
In our work during the Restorative Sleep and Vitality Program (R.S.V.P) we identified that residents in long term care communities were not receiving enough white/blue light (sunlight) exposure during the day time hours and were being exposed to too much light in the evening and overnight. Exposure to overhead lighting during night-time rounding practices makes it difficult for residents to fall back to sleep as their Melatonin levels have decreased. The effects of even a brief amount of light exposure at night are long-lasting. Some studies even site that it takes our bodies up to 45 minutes for our Melatonin levels to return to the same levels they were prior to the exposure of light.
Studies show that white/blue light exposure is stimulating to our brains and more appropriate during waking hours, while exposure to red or amber colored light does not stimulate the brain as much, thus making it a better choice for late in the day and over-night. With this added knowledge, our collaborative moved away from old practices of turning on overhead lights in resident rooms during the night. Instead, if need be, staff now wear hug lights (flashlight that wraps around the neck) with amber colored lights. We use amber colored bulbs in bedside lamps that do not interfere with Melatonin production and levels. Hallway lights and lights in common areas have been outfitted with timers to have them on at 8 am and down or off at 8 pm.
Light Tips for everyone:
• Increase sunlight exposure especially early in the day (sunlight is the best light).
• Reduce white/blue light exposure in the evening and late in the day (install an app such as f.lux to block blue light on computers, change the light setting on phones to a more amber back light, shut off the television a few hours prior to bed).
• Use amber colored bulbs in lamps.
• Use an amber colored flashlights or nightlights to navigate walking at night.
• When able, take time to get outdoors or do activities within a few feet from windows.
• Use room darkening blinds in bedrooms.
• Keep the bedroom dark at night.
When light exposure is managed well during day time and night time hours, it can be used to boost performance, improve sleep, improve alertness and increase energy.
Evidence-Based Design Meets Evidence-Based Medicine: The sound sleep study. The Center for Health Design Research Coalition. Harvard Medical School, 2010. Retrieved from: https://www.healthdesign.org/sites/default/files/Validating%%20Acustic%20Guidelines%20for20%HC%Facilities_Sound%20Sleep%20Study.pdf
Nation Sleep Foundation: What is sleep hygiene? Retrieved from: https https://sleepfoundation.org on July 10, 2018.