What if a simple change in your morning light exposure could help you sleep better?

Our sleep patterns change across our lifespan, and, as we get older, we tend to have difficulty getting a good night’s sleep and feeling well rested the next day.

Older Adults and Sleep

Older adults – 60 years old and over – generally have less deep sleep and wake up more often at night. They also sleep for shorter periods, wake up earlier in the morning and feel sleepy during the day.

Light, especially blue-enriched light (which has a higher amount of blue colours in it, like the light at midday), plays an important role in how well we sleep. This is because our sleep timing and quality is influenced by our internal body clock in the brain – the circadian clock – which relies on light and dark to stay in sync with the external environment.

Photoreceptors and Blue Light

To achieve this, humans have specialized photoreceptors – light-detecting cells on the retinas at the back of the eyes – that are highly sensitive to blue light. This is likely because we evolved to see the natural bright blue sky during the day, rather than indoor electric lights at night which are much less bright – or blue.

Age-Related Changes

As we age, our eyes change: the lens becomes thicker and yellow, and our pupil size and number of photoreceptors reduce. Less light, then, reaches the biological clock in our brain, making it more difficult to time and regulate our sleep-wake cycles.

Staying Bright

We recruited older adults (over 60 years old) with sleep problems to take part in the study. We asked them to follow a light therapy routine in which they administered blue light to themselves, at home, by sitting in front of light boxes. Each morning and evening, they spent two hours exposed to either blue-enriched or regular white light while going about their usual activities, such as reading or watching TV.

Study participants wore trackers on their wrists to measure their activity levels and sleep patterns. We found that people exposed to more hours of blue light in the morning had better sleep and more stable daily activity – likely due to improved synchronization of their internal body clock with the external environment.

Conclusion

Our findings are especially exciting because despite the messiness of real-world conditions – morning people naturally started light therapy earlier, while night owls delayed it – they align with the findings of controlled laboratory studies highlighting the real-life potential of home-based light interventions for better sleep.

FAQs

What is the connection between light and sleep? Light, especially blue-enriched light, plays an important role in regulating our sleep timing and quality.

What is the impact of aging on our eyes and sleep? As we age, our eyes change, and our pupils and photoreceptors reduce, making it more difficult for our biological clock to stay in sync with the external environment.

How can I improve my sleep? Exposure to more morning light, either by opening curtains, stepping outside, or using a bright, blue-enriched light source, can help improve sleep quality and timing.

Can I try this at home? Yes, you can try using a blue-enriched light source or a light box at home to see if it improves your sleep.