The Dark Side of Bright Lights: Are Your LEDs Harming Your Health?

LED Light Health Considerations: What You Need to Know

LED lighting has revolutionised how we illuminate our spaces, offering impressive energy efficiency and longevity. While these benefits are significant, emerging research suggests some potential health considerations worth being aware of. This post examines key areas—blue light exposure and flickering—while providing practical solutions for healthier lighting choices.

Blue Light from LEDs and Its Impact on Health

Blue light, with wavelengths between 460-480nm, is emitted in higher amounts by LEDs compared to traditional lighting technologies. This increased blue light component is inherent to how white LEDs work—most use a blue LED chip with a phosphor coating that converts some of the blue light to other wavelengths.

According to the European Commission's Scientific Committee on Health, Environmental and Emerging Risks (SCHEER), there is "no evidence of direct adverse health effects from LEDs emission in normal use (lamps and displays) by the general healthy population." However, they note that certain considerations are still important, particularly regarding blue light exposure.

How Blue Light Affects Circadian Rhythms

Our circadian rhythm—the body's internal clock that regulates sleep-wake cycles—is particularly sensitive to blue light. Research from Harvard has shown that evening exposure to blue light can suppress melatonin production and potentially disrupt sleep patterns.

According to a study published in the National Library of Medicine, "Blue monochromatic light exposure was more effective to cause a phase delay of the circadian rhythm of all subjects, which were studied in an environment free of time cues." The study revealed that blue wavelengths suppressed melatonin for about twice as long as green light, despite equal photon density.

During daylight hours, blue light exposure is natural and beneficial, helping to maintain alertness and cognitive function. It's primarily evening exposure that warrants attention.

Effects on Sleep Quality

A 2021 study published in PubMed investigated the effects of pre-bedtime blue light exposure on sleep quality. The researchers found that "Ratio of deep sleep was significantly decreased in the blue-light exposure group compared to the groups with incandescent light and blue light-blocking glasses." This suggests that blue light exposure before bedtime may reduce sleep quality by affecting the proportion of deep sleep.

Managing Blue Light

A 2020 systematic review published in Sleep Advances found that using "blue-blocking" glasses in the evening could be effective in improving sleep quality for many individuals.

LED Flickering and Visual Comfort

Understanding LED Flickering

LED flickering refers to rapid fluctuations in light output that occur when the power supply to an LED varies. While often imperceptible to the naked eye (typically occurring at frequencies above 100Hz), this flickering can affect visual comfort for some individuals.

According to Conscious Spaces, "LED lamps are super sensitive to fluctuations in electrical currents, causing a phenomenon known as 'temporal light modulation' – AKA flicker." Though imperceptible, this flicker causes the eyes to constantly adjust, which can lead to visual fatigue over time.

A study published in the Journal of Clinical and Diagnostic Research found that "office workers working under the non-flickering lights were 50% less likely to experience headaches when compared to those working under flickering lights."

The Science Behind Flicker

According to the IEEE P1789 committee, which developed recommendations for flicker in LED lighting, minimising flicker can improve the lighting experience and reduce potential discomfort such as eyestrain during prolonged exposure.

The Flicker Alliance explains that many LED light fixtures flicker, whether visibly or invisibly. This occurs because "LEDs can only be completely on or completely off, so they have to produce the flicker in order to simulate dimmer settings."

A study published in PubMed found that "Flickering lights can be uncomfortable to look at" and that discomfort increased with deviations from natural temporal patterns, particularly those with excess energy at medium frequencies.

Types of Flicker and Their Effects

The Institute of Electrical and Electronics Engineers (IEEE) P1789 committee categorises flicker effects into two main types:

1. Visually perceptible flicker (approximately 3-70 Hz): This can cause immediate effects even after brief exposure, including headaches and impaired vision.
2. Unconsciously perceived flicker (above the flicker fusion frequency): Though not consciously visible, the optic nerve and cortex can detect stimuli up to 160 Hz, and the retina itself can detect stimuli up to 200 Hz in tests. This can lead to headaches, fatigue, and reduced reading ability.

Reducing Exposure to LED Flickering

1. Choose high-quality LED products with proper drivers that minimise flicker.
2. Look for "flicker-free" certification on LED products when purchasing.
3. Test for flicker using a smartphone camera—if you see banding or stripes in the image of the light, flicker is present.
4. Follow IEEE 1789 recommendations: Recommended Practice 3 states that "for any lighting source, under all operating scenarios, flicker Modulation (%) shall satisfy the following goal: Below 90 Hz, Modulation (%) is less than 5%."

Practical Solutions for Healthier LED Lighting

The 20-20-20 Rule: A Simple but Effective Strategy

The 20-20-20 rule is a widely recommended practice for reducing digital eye strain, which can also be applied when working under LED lighting. The rule suggests taking a 20-second break every 20 minutes to look at something at least 20 feet (approximately 6 metres) away.

A 2023 study published in Contact Lens and Anterior Eye found that the 20-20-20 rule is indeed effective for reducing digital eye strain and dry eye symptoms. Researchers installed software on participants' computers to remind them to take breaks according to this rule. After two weeks, participants experienced:

• Decreased dry eye symptoms
• Reduced digital eye strain
• Improved accommodative facility (the ability to quickly shift focus)

The study concluded that "The 20-20-20 rule is an effective strategy for reducing DES and dry eye symptoms," though the researchers noted that two weeks was not enough time to see improvements in binocular vision or dry eye signs.

While some research has questioned the specific timing of the rule, the principle of taking regular breaks to rest your eyes remains sound. According to Healthline, "It takes about 20 seconds for your eyes to completely relax," making this a practical guideline for eye breaks.

Creating a Balanced Lighting Environment

1. Use warm white LED bulbs (2700K-3000K) rather than daylight/cool white (5000K+) for evening use.
2. Consider light layering - use a mix of ambient, task, and accent lighting to create a comfortable environment.
3. Install dimmer switches that are specifically designed for LED compatibility.
4. Set an evening routine that reduces blue light exposure 2-3 hours before bedtime.
5. Balance artificial light with natural light during the day when possible.

Optimising Your LED Lighting Setup

According to Meteor Electrical, there are several best practices for using LED lighting:

1. Choose the Right Bulb for the Right Application: Consider factors such as brightness (lumens), colour temperature (Kelvin), and beam angle when choosing bulbs for different areas of your space.
2. Determine the Required Brightness (Lumens): For example, a traditional 60-watt incandescent bulb produces around 800 lumens. When choosing LEDs, look for bulbs that provide similar lumens to match the desired brightness.
3. Select the Appropriate Colour Temperature (Kelvin): For a cosy ambience, opt for bulbs with a lower Kelvin rating (2700K-3000K). For task lighting or workspaces, higher Kelvin ratings (4000K-5000K) provide a brighter, more energising light.
4. Consider the Colour Rendering Index (CRI): A higher CRI indicates better colour accuracy. For areas where colour distinction is important, such as kitchens or art studios, choose LEDs with a CRI of 80 or above.
5. Check Compatibility with Fixtures and Dimmers: Ensure that the LED bulbs you choose are compatible with your existing fixtures and any dimmer switches you plan to use.

Managing Blue Light Exposure

1. Use blue light filtering glasses in the evening hours, especially when looking at screens.
2. Install blue light filtering software on electronic devices that automatically adjusts colour temperature based on the time of day.
3. Set an alarm that reminds you to turn off electronics two to three hours before bedtime.
4. Use a lamp that emits red or orange light rather than blue for reading in bed.
5. Dim the brightness of your electronic screens, or use the "night mode" feature found on some devices.
6. Consider natural lighting alternatives such as skylights to bring in natural daylight during working hours.

Conclusion

LED lighting technology offers significant benefits in energy efficiency and longevity compared to traditional lighting. By being mindful of quality and implementing some simple strategies, we can enjoy these benefits while creating comfortable, healthy lighting environments.

The key is balance—using LED lighting thoughtfully, being selective about quality, and creating lighting environments that support our natural biological rhythms. By taking a practical approach to LED lighting, we can create illuminated environments that enhance our living and working spaces.

Remember that lighting is just one component of a healthy indoor environment. Combining good lighting practices with proper ventilation, appropriate humidity levels, and ergonomic furniture can create spaces that support overall wellbeing and productivity.