Hi there! Welcome to our Wellness Wednesday Blog post. Today we are continuing our conversation about circadian rhythms and light. As previously discussed, circadian rhythms are internally driven cycles that rise and fall during the 24-hour day that help you fall asleep at night and wake you up in the morning. The master circadian clock in the brain synchronizes and controls these cycles so they work together. This circadian clock has an internally driven 24-hour rhythm that tends to run longer than 24 hours but resets every day by the sun’s light/dark cycle. Because human circadian rhythms are affected by light the light/dark cycle of the sun has a powerful effect on the circadian clock, sleep, and alertness. If you understand these effects, you can manipulate light exposure to help yourself sleep better at night and be more alert during the day. Keep in mind your circadian clock uses light and dark signals to predict what to do in the future: when to prepare you to be active and when to prepare you to sleep.
Light and Circadian Rhythms
The circadian clock is most sensitive to light from about 2 hours before usual bedtime and through the night, until about 1 hour after usual wake-up in the morning. Exposure to light during these times will affect when your body naturally gets sleepy and is ready to fall asleep.
Bright evening light 2 hours before bedtime will shift the time for sleep later, so you will tend to get sleepy and fall asleep later in the evening and will wake up later in the morning. Bright morning light will shift the time for sleep earlier, so you will tend to get sleepy and fall asleep earlier in the evening and will wake up earlier in the morning.
The color of the light also affects the circadian rhythm. Blue light has the strongest impact. Exposure to blue light (and white light, which contains blue light) during the sensitive period can make it difficult for you to fall asleep and stay asleep. Exposure to white light during the day can have positive effects, including boosting alertness and mood. Red light has no effect on the circadian clock, so you can use a dim red light at night. Yellow and orange light have little effect on the clock so you can use a very dim yellow or orange light at night.
If you have trouble falling asleep, keep the light levels dim for the 2 hours before you want to go to sleep. You can wear dark sunglasses (wraparound ones work best) if it is hard to control the light in the area. That should help you fall asleep more easily. If you are getting sleepy too early in the evening, you can go into a well-lit area to reduce the sleepiness. (However, if you are sleep deprived or fighting an infection, go to sleep early and catch up on needed sleep.) If you must get up in the middle of the night, keep light level very dim.
If you are waking up too early and cannot fall back to sleep, make sure you keep the lights very dim until the time you want to wake up. another strategy for waking up refreshed is using a sunrise stimulating alarm that eases you awake. A warm-glow light will turn on about thirty minutes before your set alarm and gradually brighten to simulate a sunrise. Exposure to this light should help bring you into a lighter sleep stage, which makes it easier to wake up when the alarm goes off. These alarm clocks typically have relaxing alarm sounds, like chirping birds—and the alarm starts quieter and gets louder, which is less abrupt to wake up to. If you cannot wake up early enough, go into a brightly lit area when you get up.
In a world where we are so tied to the internet, tv and cell phones, it is no wonder why we often feel depleted of energy, exhausted and overwhelmed. I hope you found this week’s post helpful in changing small aspects of your life to make huge transformations in the future. Sleeping well is in my opinion the first step to living a life full of wellness! Until next week!
“How to Sleep Better Naturally”. https://fourwellness.co/blog/9-natural-ways-to-get-better-sleep
Circadian Rhythms and Circadian Clocks. https://www.cdc.gov/niosh/emres/longhourstraining/clock.html