The most critical environmental component influencing sleep is light. While most individuals intuitively understand that sleeping in the dark is easier, the relationship between light and sleep is far more complex.
The circadian rhythm, the body’s internal clock that indicates when to be alert and when to rest, is regulated by light. Melatonin, an essential sleep-promoting hormone, is similarly affected by light.
While human nature developed to allow sleep to follow the daily rhythms of sunlight and darkness, widespread power now allows for lighting 24 hours a day, seven days a week. Artificial light, which brightens homes and the evening sky, is a constant element of modern life, from streetlights to office lighting to cell phones.
The sort of light we see and when and for how long we are exposed to it has a significant impact on our sleep. Understanding the complicated relationships between light and sleep will help you set up your bedroom for more consistent, high-quality rest.
What kind of light affects sleep?
Light can affect sleep in various ways, but not all sources of light have the same effect. For example, daylight, which may reach 10,000 lux (an illuminance measurement unit) in direct sunlight, is significantly more intense than bright workplace lighting, rarely exceeding 500 lux. As a result, daylight significantly impacts sleep and circadian rhythms.
There can also be significant variances between different forms of artificial light. Some have more illuminance and brightness than others. However, even light that appears to be the same brightness might have a different wavelength, altering how the eye and brain perceive it.
Blue light, for example, has a short wavelength and is emitted by many LEDs. According to studies, it has a substantially more prominent effect on melatonin and circadian rhythm than light with a longer wavelength. In addition, many electronic devices, such as cell phones, tablets, and laptops, generate blue light, which can cause sleep issues if used late at night.
How does light affect our sleep?
First, light suppresses the production of melatonin, a hormone that helps regulate our sleep-wake cycle. Light exposure during the day can make it more difficult to fall asleep at night. Second, blue light, in particular (from screens, for example) is known to reduce melatonin production more than other colors of light. Third, light can affect our body clock or circadian rhythm. Our bodies are designed to sleep during the night and be awake during the day. However, exposure to light at night can disrupt our natural sleep patterns. Finally, light can cause changes in our brain wave activity associated with wakefulness. These effects mean that exposure to light can make it difficult to fall asleep, reduce the quality of our sleep, and affect our overall energy levels.
There are several ways to reduce the impact of light exposure on our sleep. One is to avoid exposing ourselves to bright screens in the hours before bedtime. Another is to use dimmer, redder lights in the evening. And finally, we can wear blue-light blocking glasses or install software that filters out blue light from our screens. By taking these steps, we can protect our sleep and improve our overall health and well-being.
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