The way we light our evenings has a profound effect on sleep quality. Light isn’t just something we use to see-it’s a powerful signal that influences our circadian rhythm, the internal body clock that dictates when we feel awake and when we feel tired.

While natural light exposure during the day supports healthy sleep patterns, the type of artificial light we use in the evening can interfere with this rhythm, making it harder to fall asleep and stay asleep. Understanding the relationship between light and sleep can help you create an environment that supports deeper, more restorative rest.

How can light affect sleep and the circadian rhythm?

Your sleep-wake cycle is directly influenced by light exposure. In the morning, bright, blue-rich light tells your brain to wake up by suppressing melatonin, the hormone that makes you feel sleepy. As daylight fades, dim light signals the body to start producing melatonin, preparing you for sleep.

But modern life doesn’t always follow the natural light cycle. Exposure to the wrong type of light at the wrong time, particularly blue light from screens and artificial sources, can disrupt this process. This leads to delays in sleep onset, a reduced sleep cycle, and overall poorer sleep health.

The impact of artificial light exposure at night

Not all artificial light is created equal. Many LEDs, screens, and overhead lights emit high levels of blue light, which can interfere with melatonin onset and disrupt sleep patterns. Even small amounts of light exposure at night can cause:

• Delayed sleep onset – Your brain remains alert when it should be winding down.
  
• Fragmented sleep – More nighttime awakenings and lighter sleep cycles.
  
• Reduced sleep quality – Less time spent in deep, restorative sleep.
  

Research has shown that exposure to bright light at night—even for a short period—can reduce melatonin production by up to 50%, delaying the body’s natural sleep response. Over time, this can contribute to sleep deprivation, making it harder to wake up feeling refreshed.

This disruption to your sleep cycle can also have broader health effects, with links to increased stress, impaired focus, and even long-term concerns such as metabolic issues and weakened immune function.

How to minimise the effects of light on sleep

Creating a light-conscious bedtime routine can help align your circadian rhythm and improve sleep quality. Here’s how:

• Reduce blue light exposure in the evening – Avoid screens or use a blue light filter at least an hour before bed.
  
• Switching your lighting – Opt for lighting without a spike in sleep-disrupting blue wavelengths.
  
• Limit overhead lighting – A softer, more focused light in your bedroom can help signal to your body that it’s time to rest.
  
• Maintain a consistent sleep schedule – Going to bed and waking up at the same time each day reinforces healthy sleep patterns.

Natural light for better sleep

While much of the focus is on limiting artificial light at night, it’s just as important to get enough natural light during the day. Exposure to bright, natural light in the morning and early afternoon helps regulate the circadian rhythm, ensuring the body recognises the right signals for sleep when evening arrives.

Lack of natural light exposure can lead to circadian misalignment, where the body struggles to differentiate between day and night. This is especially common in the winter months when daylight hours are shorter, leading to a sluggish body clock and disrupted sleep schedules.

To encourage better sleep, try to spend time outdoors daily, even on cloudy days, or position yourself near a window to absorb ambient light during the day.

Light smarter for better sleep

Sleep disturbances are often linked to the way we use light, yet it’s one of the easiest factors to control. By making small adjustments - such as reducing artificial light at night, minimising blue light exposure, and embracing natural light habits during the day - you can support a healthier, more balanced sleep cycle.

Good sleep starts long before you close your eyes. It begins with the right light exposure.

The key to better sleep isn’t just switching off - it’s lighting wisely.