We often think of sleep as simply a matter of tiredness. In reality, it’s also a matter of signals. And the most powerful signal—the one that tells the body “it’s daytime” or “it’s nighttime”—is light. When there’s too much light in the evening or too little in the morning, the body’s internal clock gets thrown off. This can lead to falling asleep later, waking up more easily, or feeling like you haven’t fully recovered.
Table of Contents
- • Understanding the connection between light and sleep
- • In the morning: set the clock to the correct time
- • In the evening: dim the lights to let night fall
- • Screens: What Really Matters
- • In the bedroom: darkness, warmth, little details
- • Scientific References
Understanding the Connection Between Light and Sleep
Sleep is governed by two interrelated factors. On the one hand, there is “sleep pressure”: the longer we stay awake, the greater our need for sleep becomes. On the other hand, there is the circadian rhythm: a biological clock that regulates the day-night cycle in the body. This clock does not operate in a vacuum. It constantly adjusts itself based on the environment, and light is its primary cue.
That’s why the same time of day doesn’t feel the same depending on the season, exposure to daylight, or the type of lighting at home. When evening light resembles prolonged daylight, the body may delay certain nighttime signals, including melatonin secretion (often described as one of the signals that accompany falling asleep). Conversely, if the days are too dark, the morning may lack a “kickstart,” and the rhythm becomes less distinct.
In the morning: Set the clock to the correct time
In the morning, light plays a very specific role: it signals to the body that the day is beginning. Many people sense this intuitively: when you’re exposed to bright light early in the day, you often wake up feeling more “alert” and have more consistent energy levels throughout the morning. Conversely, a very dark morning spent solely under indoor lighting can make it feel like the day is getting off to a slow start.
The simplest adjustment is nothing complicated: open the shutters early, stand near a window, or step outside for a few minutes if possible. Even without exercising, exposing yourself to natural light helps establish a rhythm. And if you’re going through a period of transition (a change in season, shifting schedules), this consistency becomes even more helpful. On this topic, you can also read our article on how seasonal changes affect sleep.
In the evening: dim the lights to let night fall
In the evening, the need is almost the opposite: to help the body realize that the day is coming to an end. Again, it’s not a matter of doing it right, but of consistency. Soft, dimmer lighting—especially in the two or three hours before bedtime—helps create a more restful environment. It prevents a feeling of hyperarousal and promotes a calmer transition.
Two factors often matter more than we realize: intensity (too much light too late) and the nature of the light spectrum (very cool, very white lights tend to be more stimulating). Warmer, dimmer, more localized lighting doesn’t prevent you from enjoying the evening. It simply changes the atmosphere and the message sent to the brain.
Studies on evening light exposure show that “excessive” light can delay certain nighttime cues. This isn’t a condemnation of lamps or screens—it’s an invitation to return to a more natural rhythm, like a home-made twilight. At Kipli, we love this idea: removing distractions tolet the night do its work.
Screens: What Really Matters
When it comes to screens, there’s often a misunderstanding: people talk about blue light as if that were the only issue. In reality, what disrupts sleep is often a combination of factors: light close to the eyes, high brightness, and—above all—content that keeps the brain active (messages, information, videos, work). Light is just one piece of the puzzle—but an important one.
If you already have a bedtime routine, you can easily incorporate light into it without making it too rigid: dim the lights at the same time every night, switch to a lower light source (such as a table lamp instead of a ceiling light), and keep your bed as a place for rest. It’s often this simple repetition that makes the biggest difference.
In the bedroom: darkness, warmth, little details
The bedroom is a place where we seek one thing above all else: a stable environment. Sufficient darkness helps limit the subtle cues that keep us awake. Small lights (from chargers, routers, or very bright alarm clocks) may seem harmless, but they can become constant cues, especially for sensitive sleepers. Again, the goal isn’t to control everything, but to eliminate what is clearly unnecessary.
And when you leave a light on in the evening, it’s often best to make it “calmer”: avoid a very white ceiling light and opt for a softer, warmer, more diffused light source. A linen pendant light naturally fits the bill: it filters and softens the light, creating a less stimulating atmosphere in the minutes before bedtime.
For a more subdued atmosphere before bedtime, you can choose a linen pendant light, such as the PURE Linen Pendant Light, or the PURE Mini Linen Pendant Light if you’re looking for a more discreet size. The idea isn’t to provide more light, but to provide better light: softer, lower, simpler.
There’s also the issue of temperature. Sleeping in a room that’s too warm often leads to lighter sleep. A slightly cool bedroom with dim lighting creates a more “nighttime” atmosphere. And when your body is supported steadily (by your mattress and pillow), you move less to compensate. If you’d like to learn more about the importance of a consistent sleeping environment, our 100% natural latex mattress was designed with this in mind: breathability, stability, and transparent ingredients. Nothing more—just what helps.
Scientific References
To gain a more detailed understanding of the role of melatonin and the biological clock, the resources from Inserm are a good place to start. Regarding exposure to artificial light in the evening, you can also consult experimental studies such as Chang et al. (2015) on the use of e-readers before bedtime, or Gooley et al. (2011) on the effects of light in the evening. And for general guidance on sleep hygiene (including the importance of a dark and quiet environment), the CDC offers an accessible summary.
Kipli, plain and simple.