Light and sleep

How light affects your sleep

Our bodies are strongly influenced by light. Melatonin — the hormone responsible for regulating our sleep-wake cycle — is affected by light exposure. When it gets dark, the body produces more melatonin, helping us fall asleep. Exposure to light, particularly blue light, can suppress this production and make it harder to fall asleep.

• Daylight: Bright daylight, especially in the morning, helps your body regulate its circadian rhythm. It increases alertness and helps you sleep better at night.
• Artificial light: Artificial light sources — such as those from electronic devices — can disrupt melatonin production. This is especially true for blue light emitted by smartphones, tablets, and computers.
• Dark environment: A dark sleep environment is essential for good sleep. Light can disturb your sleep and wake you during the night.

The role of cortisol and morning light

Cortisol, often known as the stress hormone, also plays an important role in our sleep-wake cycle. It serves several functions, including regulating blood pressure, suppressing inflammation, and raising blood sugar. Less well known is that cortisol also plays a key role in waking us up.

• Morning cortisol peak: Cortisol has a daily peak in the early morning, roughly 30–45 minutes after waking. This peak helps us wake up and start the day. Its timing is strongly influenced by morning light exposure.
• Morning light exposure: Exposure to bright morning light helps synchronise the cortisol peak with your natural wake-sleep cycle. This means morning light not only helps regulate melatonin, but also optimises the timing of cortisol production — so you wake up more easily and stay more alert throughout the day.

Tips for better sleep through light management

Optimise your daylight exposure

Make sure you get enough daylight during the day, especially in the morning. This helps regulate your internal clock and supports your sleep-wake cycle.

Tips:

• Spend time outdoors, especially in the morning.
• Position your workspace near a window to get as much natural light as possible.
• Go for a walk during your lunch break to soak up extra daylight.

Limit blue light exposure in the evening

Blue light from electronic devices can suppress melatonin production and make it harder to fall asleep.

Tips:

• Avoid using electronic devices such as smartphones, tablets, and computers at least an hour before bed.
• Use night mode on your devices, which reduces blue light output.
• Consider blue light filter glasses for use in the evening.

Create a dark sleep environment

A dark bedroom helps your body produce melatonin and reach deeper sleep.

Tips:

• Use blackout curtains to block outside light.
• Avoid night lights, or use a very dim one if necessary.
• Switch off all light-emitting devices or cover them to make your sleep environment as dark as possible.

Use smart lighting

Consider smart lighting that you can adjust to match your sleep-wake cycle.

Tips:

• Set smart lights to be bright in the morning to help you wake up, and dimmed in the evening to help you wind down.
• Use bulbs that can change colour temperature — warmer light in the evening and cooler, bluer light in the morning.

Conclusion

Light has a significant impact on your sleep quality. By managing your light exposure carefully, you can optimise your sleep-wake cycle and achieve better rest. Get enough daylight, limit blue light in the evening, create a dark sleep environment, and consider smart lighting. Try these tips and see how they improve your sleep.

Further information

For more tips on sleep and health, visit our other blog articles on sleep and wellbeing.