How light affects our sleep
Sleep is influenced by many factors. Stress, insufficient exercise and poor nutrition can have a negative effect on our sleep and, consequently, on our health.
However, one of the biggest influencing factors is light. Over the past decades, the way we are exposed to light has changed dramatically. This is mainly due to the invention and ubiquity of artificial light - from the light bulb to smartphones and tablets. Unlike our ancestors, we can consume light regardless of the time of day - and not without affecting our restful sleep patterns.
Light regulates our biological rhythm.
Our body is bound to a time cycle, the circadian rhythm. Activity levels, metabolism, heart rate, body temperature and hormonal activity increase or decrease according to our internal clock. For the most part, these activities peak during the day - usually in the afternoon - and sink to their lowest level while we sleep. Maintaining this rhythm is dependent on sunlight. Receptors in our eyes take information from sunlight and use it to regulate the circadian rhythm.
To maintain and promote this rhythm, it is important to receive bright light of the entire spectrum (= daylight) during the day and to reduce blue light in the evening. Blue light in the evening is associated with shorter sleep and poorer sleep quality. Both in turn lead to increased fatigue the following day and lower cognitive capacities.
How can I use light to optimize my sleep?
- Try to maintain a natural rhythm of light during the day and darkness at night
- To anchor the inner clock and set it "right", spend 30-60 minutes a day outside in daylight
- 10 minutes of daylight before 10 a.m. improves the sleep of the next night and leads to more recovery
- Avoid blue light in the evening by dimming the light and using a blue light filter on smartphones, tablets and notebooks
If you want to learn more about this topic, we recommend this TedTalk: https://www.youtube.com/watch?v=nrwF6oVaa0k
Gerrig, Richard J.; Zimbardo, Philip G.(2008). psychology. 18th, updated edition. Pearson Eduction. Munich, Germany.
