How Light Exposure Impacts Circadian Rhythms And Sleep?

Article Highlights: - Light exposure has a huge impact on sleep/wake cycles. - Exposure to natural light throughout the day can help you stay alert and awake. - Artificial lights at night can disturb our daily rhythms and disrupt sleep. - Seek bright natural light during the day and darkness at night consistently for the best night’s sleep.

The sensation of being tired all day only to start feeling alert right when it’s time to go to bed is frustrating and unfortunately increasingly common. But why does this happen? Why does it seem like our bodies are betraying us? Research surrounding circadian rhythms are beginning to uncover the importance of light in shaping the way we feel throughout the day.

Circadian rhythms are daily biological cycles that coordinate the activities in the body. Throughout our evolution, light from the sun gave us the cues our bodies needed to organise internal activities such as body temperature, hormonal fluctuations and alertness. As we’ve begun to live more of our lives indoors with artificial lights, we’ve become detached from the natural light cycles, causing disruptions in our daily rhythms. These disruptions can contribute to a host of diseases including overweight, type 2 diabetes, cancer, cardiovascular disease, stroke and infection.

We now seem to live in a world where we’re out of bright natural sunlight during the day, and then exposed to strong artificial lights at night time. This is almost the polar opposite light exposure when compared to the way we evolved. This is a substantial factor in the increasing prevalence of insomnia and lack of sleep generally. To make things worse, our eyes are exquisitely tunes to specific spectrums of light to organise our biological functions. We are very sensitive to the colours blue and green, the colours that modern lights and tech devices give off. This tells our brains that it’s always the middle of the day, making it difficult to fall asleep immediately after turning our devices off.

So what can we do about this? Artificial lights and tech devices are everywhere, and we’ve become rather dependant on them in our daily lives. Fortunately, there are small steps you can make to moderate the impact of artificial lights on our sleep:

1. Change you light globes to ‘warm’ incandescent globes. Warm globes emit more red and infrared light than LEDs and Fluorescent globes, lessening the impact of the light on your circadian rhythm. Look out for globes that have either a colour rendering index of 100 or have a colour temperature of at most 2700K. These lights will be the most circadian friendly.
2. Put a blue light filter on your devices. Most devices use lights that emit almost exclusively in the blue/green region. However, most phones and other similar devices will have the option for a blue-light filter, making the screen an orangy/red colour.
3. Get outside in natural sunlight during the day. We need strong natural light during the day to help set our circadian clocks. Light intensity outside is often about 1000x greater than indoors in artificial lights. Getting outside and viewing some bright light from the sun helps to inform your body that it’s daytime.
4. Get 10 minutes of sunlight at sunrise and sunset. When the sun is just rising or setting, the colour spectrum that makes it through the atmosphere is unique. This spectrum communicates with special cells in our eyes to tell us that it’s time to either wake up or get ready to wind down.

By taking the time to incorporate some of these strategies into your daily routine, you’ll be able to strengthen your circadian rhythm and change the way your body behaves throughout the day. You’ll feel more awake after you get out of bed and more tired once the sun has gone down. Making time to take care of your circadian health is an important step in making sure you get a great night’s sleep.