Right about now you might be thinking, “Um, Ryan, I sleep with the lights off. How can changing them make me sleep better or more?”
Contrary to what you might be thinking, I haven’t fallen off my rocker. Changing at least some of the lightbulbs in your home does have the potential to improve your sleep. As can wearing a specific type of glasses or reading an actual paper book instead of an iPad in the evening hours. (More on that later.)
It’s all related to our circadian rhythms and one major factor that influences those rhythms. Let’s go over the (extremely abbreviated) basics:
Light and Our Bodies’ Daily cycles
You’ve probably at least heard the term circadian rhythms before. In The Circadian Code, Satchin Panda, PhD explains that “circadian comes from the Latin circa, meaning ‘around’ (or ‘approximately’), and diēm, meaning ‘day'”. So circadian rhythms are biological processes that occur on a roughly daily basis. He goes on to say that these processes are present in all plants and animals and that each of our organs have their own rhythm which is interconnected and influenced by those of other organs.
In humans, the circadian “master clock” resides in our brains and is influenced by our eyes’ exposure to light. When specific light-sensing proteins that exist in some of our retinal neural cells are exposed to full-spectrum light—more specifically, melanopsin sensing the blue wavelength—our brains interpret that exposure to mean it’s daytime and we should be awake. When (blue) light is not present, our brains interpret the lack of that wavelength to mean it’s nighttime and we should be preparing for sleep.
This is where problems with our modern lifestyles arise. For most of human existence, we weren’t able to control light. When the sun set, we went to sleep. When it rose, we woke up. However, now we can (and do) expose ourselves to blue light—from computer, TV, and phone screens as well as bright LED or fluorescent overhead lights—at all hours of the day and night.
That really messes with our melatonin production, the hormone that regulates sleep. In fact, in one study referenced by Matthew Walker, PhD in Why We Sleep, the book I referenced in last week’s tip:
Compared to reading a printed book, reading on an iPad suppressed melatonin released by over 50% at night. Indeed, iPad reading delayed the rise of melatonin by up to three hours, relative to the natural rising the same individuals experienced when reading a printed book. When reading on the iPad, their melatonin peak, and thus instruction to sleep, did not occur until the early morning hours, rather than before midnight. Unsurprisingly, individuals took longer to fall asleep after iPad reading relative to print-copy reading.
So the moral to this story is that you’d be wise to manage your exposure to blue light at certain times of the day if you want to improve the quality and quantity of your sleep.
Putting it into practice
Here are a few ways you can begin to do just that (with extra details for shift workers):
- Get some exposure to bright light as soon as possible after you wake. Sit by an east-facing window or, better yet, go for a ten-minute walk before heading off to work. (Exercise has some of its own circadian rhythm-boosting power.) If you’re a shift worker, catch as much of the waning daylight as you can after waking and before heading to work.
- Adjust the lights in your home. Observe where you generally spend the most time in the morning and evening hours. Then install bright “daylight” LED or fluorescent bulbs in the rooms where you spend most of your morning time and dimmer, orange-colored bulbs in the rooms where you spend the evening hours. (Orange-colored light doesn’t activate melanopsin but obviously still allows you to see around the room.)
- Put away your screens an hour before bed. Again, this includes computer screens, the TV, and your phone. If you absolutely must be exposed to one of these screens within an hour of your bedtime, use the “nighttime” mode, which skews the colors toward the red end of the light spectrum and away from the blue, and consider investing in a high-quality pair of blue light-blocking glasses. And if you happen to be a shift worker, wear sunglasses on your way home from work, and consider investing in some light-blocking shades for your bedroom (if you haven’t already).
Combine one or more of these options with a consistent bedtime routine and schedule, and you’ll be well on your way to catching a few more z’s on a regular basis.