We live in a world where screens are everywhere, from laptops at work to phones on the sofa and tablets in bed. It seems harmless: just a quick scroll before bedtime. But did you know that the blue light from your screens can have a direct impact on your sleep and even your hormonal balance? In this article, we delve into the world of melatonin, blue light and the broader effects on your health.
In this article, you will read:
- What melatonin is and what it does
- What your circadian rhythm is
- How blue light affects your circadian rhythm and melatonin
- How this impacts your hormones
- Tips for good melatonin production
What is melatonin?
Melatonin is known as the ‘sleep hormone’. The body produces melatonin from the neurotransmitter serotonin. This happens in the pineal gland in our brains when it gets dark. As soon as the light dims, your body starts producing melatonin to prepare you for sleep.
What does melatonin do?
Melatonin regulates your circadian rhythm, or biological clock. The term circadian is derived from the Latin circa diem, which means “around a day”. It refers to the natural 24-hour rhythms in our bodies.
The circadian rhythm plays a key role in processes such as our sleep-wake cycle, hormone release, digestion, body temperature and other essential bodily functions. Almost all living organisms have a circadian rhythm, from humans to plants and animals. In flowers, this rhythm ensures that they open or close at the right time.
When we are exposed to light in the evening, especially blue light, the production of the sleep hormone melatonin is suppressed, keeping us alert for longer. This can disrupt our natural rhythm and lead to sleep problems and reduced energy during the day.
What is blue light?
Blue light is a form of visible light with a short wavelength and relatively high energy. It is found in sunlight, which is good during the day because it keeps you alert and awake. Nowadays, however, we are also exposed to artificial sources of blue light, such as smartphones, laptops, tablets, televisions and LED lighting. Artificial blue light does not have the same natural rhythm and intensity as sunlight and can therefore tire your eyes, affect your concentration and disrupt your sleep-wake cycle.
How blue light affects melatonin production
Blue light from sunlight has a positive function during the day: it keeps you alert and awake. But in the evening, it has the opposite effect. When you look at a screen in the evening, your brain sees that artificial light as a signal that it is still daytime. This suppresses or delays the production of melatonin. Exactly the opposite of what your body needs to sleep.
Even one hour of exposure to blue light in the evening can be enough to reduce your melatonin production. The result?
- More difficulty falling asleep
- Restless sleep
- Shorter sleep duration
- Reduced sleep quality
Science confirms this: a study by the RIVM showed that young people who use a screen in the hour before bedtime sleep less well: they fall asleep later, sleep for shorter periods and wake up more often. As a result, they are more tired during the day. These complaints decrease if they do not use a screen in the evening or wear orange glasses that block blue light.
Impact on other hormones
The impact of blue light extends beyond just your sleep. In the long term, it can affect your energy, mood and overall health. Chronic sleep deprivation and a disrupted biorhythm can lead to hormonal imbalance. Some examples:
- Cortisol: Your stress hormone remains elevated, leading to fatigue, tension and difficulty recovering.
- Ghrelin & leptin: These hormones regulate your feelings of hunger and satiety. Sleep deprivation increases ghrelin (more hunger) and decreases leptin (less satiety), leading to increased eating.
- Testosterone & growth hormone: Poor sleep lowers these hormones, which affects muscle recovery, libido and energy levels.
Sleep is not just rest, it is literally recovery at a hormonal level. If this is disrupted, your hormonal balance is automatically disrupted as well.
Tips for healthy melatonin production
Fortunately, there are ways to reduce the negative effects of blue light in the evening and reset your biological clock:
- Use a blue light filter on your phone or computer. Many devices have a built-in ‘night shift’ or ‘night mode’. Or install software such as f.lux.
- Limit screen time in the evening: make sure you don't look at any screens for at least an hour before bedtime. Instead, create a soothing evening ritual. Relaxation helps your body produce melatonin. Think of reading, taking a warm shower, doing breathing exercises or meditating.
- Use warmer lighting in the evening (think candlelight or warm LED lamps).
- Wear blue light glasses if you have to use screens in the evening.
- Go outside in the morning: Morning daylight helps to regulate your biological clock. Even 15 to 30 minutes outside can strengthen your melatonin rhythm.
- Limit caffeine and heavy meals in the evening: Caffeine can disrupt your melatonin production, as can eating late and heavily. Opt for light, soothing foods in the evening.
- Make sure your bedroom is dark: Use blackout curtains or a sleep mask. Even small light sources, such as an alarm clock or standby light, can disrupt melatonin production.
- Use a daylight lamp: Light therapy with a special daylight lamp can help you reset your biological clock. These lamps mimic natural morning light and are especially useful for disrupted sleep patterns or during dark winter months.
- Make sure you get regular exercise: Exercise supports your biological rhythm and contributes to deeper, better sleep. Try to be active every day, preferably during the day. Avoid intense exercise just before bedtime, as this can actually make you more awake.
Conclusion
Blue light may seem harmless, but it has more of an impact on your body than you think. The good news? You don't have to make big changes to limit that effect. With just a few small adjustments, such as less screen time before bed or using warm light in the evening, you can already positively influence your melatonin production.
Melatonin is a powerful, natural aid that your body produces itself as long as you give it the right conditions. Small steps can make a big difference to your sleep, energy and overall health in the long term.
