In our modern lives, screens are an integral part of our daily routine. Smartphones, computers, tablets, and televisions expose us to a particular type of light: blue light. Although it is not only present in screens (it occurs naturally in sunlight), its influence on our bodies is often underestimated. One of the most important aspects to understand is its role in regulating our circadian rhythm, i.e., our internal biological clock.
What is the circadian rhythm?
The circadian rhythm is a biological cycle of approximately 24 hours that regulates our periods of wakefulness and sleep. It is controlled by a small region of the brain, the hypothalamus, which adjusts our bodies according to the ambient light. It is this cycle that helps us to be awake and focused during the day, and then to feel tired and sleep at night.
Blue light: ally during the day, enemy at night
Blue light plays a key role in this process.
- During the day: it stimulates our alertness, improves our cognitive performance, and supports the secretion of cortisol, the energy hormone. It therefore helps to keep us awake and productive.
- In the evening: excessive exposure delays the secretion of melatonin, the sleep hormone. As a result, it becomes more difficult to fall asleep, sleep is less deep, and recovery is less effective.
The effects of circadian disruption
When our circadian rhythm is disrupted by prolonged exposure to blue light in the evening, several consequences can arise:
- Difficulty falling asleep and insomnia.
- Chronic fatigue and decreased concentration.
- Mood imbalance, sometimes linked to anxiety or depression.
- In the long term, repeated disruption of the circadian rhythm may also be associated with an increased risk of metabolic and cardiovascular diseases.
How can you protect your circadian rhythm?
Here are some simple tips to help you maintain a healthy balance:
- Get plenty of natural light in the morning: it helps to “set” your biological clock.
- Limit screen time in the evening: ideally, avoid screens for at least an hour before bedtime.
- Use blue light filters: glasses with filters or “night mode” settings on electronic devices.
- Create an atmosphere conducive to sleep: dim lighting in the evening, a dark and cool bedroom at night.
Blue light is not inherently bad. On the contrary, it is essential for stimulating our bodies and maintaining good energy levels during the day. But, as is often the case, it is excess exposure and, above all, the timing of exposure that causes problems. By learning to better manage our exposure to blue light, we can preserve our circadian rhythm and thus improve the quality of our sleep, our mood, and our overall health.
