Sunglasses are a summer essential. They protect our eyes from UV rays, reduce glare and add a touch of style to our outfits. But have you ever considered their impact on your circadian rhythm? This biological cycle, which regulates our sleep and energy levels, is closely linked to light. So could wearing sunglasses throw off your internal clock? Let's find out.
Understanding the circadian rhythm
The circadian rhythm is a natural 24-hour cycle that influences several physiological functions, such as sleep, body temperature, hormone production and appetite. It is mainly regulated by light: when light enters our eyes, it sends a signal to an area of the brain called the suprachiasmatic nucleus (SCN), which acts as a master biological clock.
Blue light, especially in the morning, signals to the body that it's time to be awake and active. In the evening, the absence of light indicates that it's time to produce the sleep hormone melatonin.
What role do sunglasses play?
Sunglasses, especially those with very dark or polarized lenses, considerably reduce the amount of light reaching your eyes. If you wear them frequently - and especially early in the morning or on cloudy days - this could send the wrong message to your brain: it thinks it's still dark, which can delay your body's waking up and disrupt the synchronization of your circadian rhythm.
The right time to wear them
This doesn't mean you shouldn't wear sunglasses! They're essential for protecting your eyes from UV rays, preventing cataracts, macular degeneration and other eye ailments. However, here are a few tips to avoid disrupting your biological rhythm:
- Expose yourself to natural morning light without sunglasses for the first 20 to 30 minutes of your day, conditions permitting.
- Wear your sunglasses when the sun is at its zenith, or when there's a lot of glare (at the beach, in the mountains, on the water).
- Avoid sunglasses that are too dark if the light is not intense - they could block an unnecessarily high amount of light.
Wearing sunglasses can influence your circadian rhythm, but only if you overdo it, especially early in the day. As with many things, it's all a question of balance. Take advantage of the morning light to get your day off to a good start, then protect your eyes as the sun becomes more intense. Your eyes, and your sleep, will thank you.
