Light, Temperature, and Your Good Night’s Sleep

Sleep is a delicate process that can easily be interfered with. There are several outside factors that play a part in improving or disrupting sleep, including light from artificial sources and temperature ranges. In this article, we’ll explore how temperature and light mix with sleep, and how you can create the ideal bedroom environment with optimal light and temperature for maximum sleep.

How Temperature and Light Affect Sleep

Our internal clocks are set based on the rising and setting of the sun. This is known as our circadian rhythm, and it’s the basis for why we feel awake and tired and the same times every day. The human race had no issues with sleep schedules until the invention of the light bulb. From then on, our ability to lengthen “daylight” meant the end of easy, natural sleeping. Our bodies produce melatonin as it grows dark outside, and our body slowly eases into sleepiness. But with lights in our houses, as well as light emitted from our mobile devices, our bodies have a hard time determining when it’s truly bedtime.

Temperature also plays a role in our natural process of going to sleep. As our brains produce melatonin, our bodies respond by becoming (on average) a degree or two colder. Scientists have learned that trying to sleep when you’re too hot or cold can be difficult because our bodies crave a certain ideal temperature for sleep. Experts suggest that you keep your room between 60-68 degrees Fahrenheit.

So, as night falls, our brains cue us to feel tired and the body temperature decreases as the metabolism slows. That means it should be easy enough to enjoy a good night’s sleep, yet millions of us don’t. Why not? Scientists point to our love of all things electronic.

What Is “Lux” and How Does It Affect Sleep?

Light is never just “light.” It has lux, lumen, and wavelengths, and each of them can interfere with good sleep. Let’s look at lux and lumen. The latter is “a measurement of light intensity or brightness, also known as radiance, at the source of the light itself.” On the other hand, lux uses lumen values but also looks at the impact that light has on the space around it. To illustrate this, a small nightlight has a specific lumen, but its brightness in the room is its lux. Standard lux readings in a home are around 300-500, but in the evening and during the hours before bed, it should be less than 180. After you turn out your lights, it should not be more than 5.

There are also wavelengths in light, and blue wavelengths, in particular, can pose a problem.

Blue Light and Bedtime

Blue light, according to Harvard Medical School, “is beneficial during daylight hours because they boost attention, reaction times, and mood—seem to be the most disruptive at night…While light of any kind can suppress the secretion of melatonin, blue light at night does so more powerfully.”

The big question is why, and the answer is not surprising. If it nurtures alertness, it makes sense that blue light might interfere with melatonin (that brain chemical responsible for making us feel tired at night). It does just that, and because our smartphones and devices emit blue light, it’s getting harder to avoid.

Fortunately, there are a few ways you can avoid the problems associated with blue light. There are blue light filters on the latest smartphones and various apps that have downloadable filters as well. The best way to steer clear of this harmful light is to turn off all electronics at least one hour before bedtime. This will also help relax you and get you ready to unwind before sleep.
Between finding the right temperature for your room and blocking all artificial and blue lights at bedtime, it’s a lot to remember. But with all the benefits these changes offer, it’s worth taking the time to make these small updates.

“Effect of Light on Human Circadian Physiology”.US National Library of Medicine, National Institutes of Health.
“The Ideal Temperature for Sleep”
“Darkness Matters- How Light Affects Sleep”.S+ ResMed.
Blue Light Has a Dark Side”.Harvard Health Publishing.
Published on: August 20th, 2017 by: Leah Perri

Last modified on November 26th, 2018

With the world’s most advanced
sleep improvement system

Download for FREE!

Subscribe to stay informed about all the ways to improve your sleep