Advanced Blue LEDs may Assist in Regulating Sleep-Wake Cycles

Scientists have created and assessed ‘human-centric’ LEDs, which emit varying wavelengths of blue light based on the time of day, aiming to minimize the disruptive impact of artificial light on our circadian rhythm. They anticipate that manufacturers will adopt their discoveries to manufacture these innovative LEDs.

As our circadian rhythm is aligned with the natural light-dark cycle, it is crucial to have appropriate exposure to light. However, in our contemporary society, many individuals encounter excessive indoor artificial light, which can disturb our circadian rhythm and result in disrupted sleep.

Understanding the Impact of Blue Light on Sleep Preparation and Circadian Rhythm Regulation

More than any other color, blue light interferes with the body’s ability to prepare for sleep by deceiving the brain into perceiving it as daytime, thereby suppressing the production of melatonin, the ‘winding-down’ hormone. The eye’s retina contains intrinsically photosensitive retinal ganglion cells (ipRGCs) that are especially responsive to the absorption of blue light with a wavelength of 480 nm. Previous studies have indicated that wavelengths ranging from 460 nm to 500 nm play a role in regulating our circadian rhythm.

In response to the disruptions caused by blue light on bodily rhythms, researchers have developed a ‘human-centric’ LED that is engineered to emit the appropriate type of blue light at specific times of the day.

Recognizing the influence of two distinct light wavelengths on circadian rhythm, the scientists devised two LEDs: one emitting a ‘daytime’ wavelength at 480 nm and the other emitting an ‘evening’ wavelength at 450 nm. These LEDs were integrated into bulbs, and phosphors within the bulbs were employed to convert some of the blue light into red and green, mimicking the conventional bulb spectrum.

Human-Centric LED vs. Conventional LED Lighting in a Controlled Environment with Participant Randomization

In a room lacking windows but furnished with a desk, treadmill, and bed, the Human-Centric LED (HC-LED) bulbs, alongside conventional LED (c-LED) bulbs (480 nm), were installed in ceiling fixtures. Twenty-two healthy adult male volunteers participated in the study, randomly assigned to either HC-LED or c-LED lighting. Over a three-day period, participants experienced both types of lighting, as well as natural daylight/nighttime lighting, while electronic devices with blue-light filters were permitted.

Saliva samples were collected from participants at 15 time points over a 50-hour period, encompassing various lighting conditions, even during the midnight to 3:00 a.m. timeframe. Despite the sleep disruption for sample collection, participants exhibited a well-established circadian rhythm. The study revealed that exposure to Human-Centric LEDs (HC-LEDs) increased nighttime melatonin levels by 12.2% and decreased daytime melatonin by 21.9% compared to exposure to conventional LEDs (c-LEDs).

Researchers Urge Integration of HC-LED Technology into LED Lamps and Electronic Displays to Address Daytime Melatonin Suppression

The researchers aspire to see manufacturers of LED lamps and electronic displays incorporate their findings to produce HC-LEDs. While many displays, including smartphones, televisions, and computer monitors, offer a mode for blocking blue light at night (BLAN), there is currently no mode that can promptly suppress melatonin by intensifying blue light during daytime hours.

According to the researchers, “The HC-LED, designed to enhance the circadian rhythm by directly controlling the wavelength band of light associated with melatonin, will prove valuable in preserving a healthy circadian rhythm in today’s indoor-centric lifestyle.”

Read the original article on: New Atlas

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