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Use LED lighting for better circadian rhythm

Circadian lights

Lots of discussion is going on the effect of lights on the human body. Whether you call it biological lighting, human-centric lighting or circadian lighting, all mean the same – physical and physiological effects of light on our body.

Apart from giving the ability to see things, light also has impacts on our Circadian Rhythm. It is a built clock in your body that controls our daily energy levels, behavior, sleep-wake cycle, and mental awareness. This is the clock that makes us feel energetic in the daytime while we feel sleepy at night. It means human eyes and brain takes ideas from the day and night cycle that tells the body when to remain active and when to take a sleep. A tuned Circadian Rhythm results in optimized productivity, proper sleep and fewer diseases.

How does it work?

retinaTo understand these functions, you must know the discovery of ipRGCs (intrinsically photosensitive retinal ganglion cells) in the retina. If these cells will not receive any light for two hours, it sends signals to the hypothalamus to release melatonin, which triggers sleep or circadian cycle. You must have seen individuals facing trouble getting into sleep after watching television or working on laptops at night. It is because of the blue light emitting from the display of these devices. Blue light is effective in boosting awareness and attention in the daytime while it does opposite at night by reducing the secretion of melatonin, hence disturbing sleep and causing other harmful effects.

Respite from lifestyle related problems

sleep patternToday’s working culture forces us to stay indoors ninety percent of the time staring at artificial displays. Due to such habits, Circadian Rhythm is unable to sync with the day/night cycle. Living in artificial light environment messes up with our sleep patterns and results in high rates of diabetes, cancer, heart diseases, and ulcers. Such disorders are common among night shift workers and abrupt sleep cycle is one of the main reasons.

After understanding these facts, manufacturers are producing lights that can maintain the Circadian Rhythm. Even the precisely tuned lights have effects depending on the psychological state of an individual. Moreover, the right light at the wrong time can totally change its effects. These are the reasons why some of the makers are successful while few failed.

Circadian-effective LED lighting

Circadian-effective LED lightsImage Source : cltc.ucdavis.edu

Light rays with a wavelength below 500 nm (nanometer) affect the Circadian rhythm of the human body – photoreceptors present in the retina has peak sensitivity at 480 nm and lights with a short wavelength of 460-480 nm reduce the melatonin secretion. So, how do we design LED lights that will support our Circadian Rhythm? The solution came with the LED that has the ability to throw dim and mixed lights. LED gave birth to circadian lighting, which a setup to carry temperature and illumination change throughout the day.

Circadian-effective LED lights are described on the basis of their CCT (correlated color temperature) that is measured in Kelvin (K). LED lights with high CCT will be compared to daylight to provide benefits after sunrise while low CCT lights are beneficial for after sunsets. Similar to sunrise and sunset that starts at 5,500K and ends at 3, 400K respectively. The idea is to create a blue spectrum light during the daylight that will suppress melatonin releases while maintaining a warm color environment when the body should be relaxing. Blue lights have high CCT and fall in the 460- to 490-nm range.

Productivity Boost

Productivity BoostWorkplace lights should emit blue wavelength light to increase concentration and energy levels. Resting places should have warm white lights to promote sleep. Circadian lighting is a proven method to boost productivity in the working environment while helps recover patients in a fast and better way at healthcare environments. Educational establishments have reported better concentration in students after installation of circadian-effective lights. NASA used the technology at ISS (International Space Station) to improve the productivity and sleep of their employees. These are examples, but we all know that a good light engages and strengthens the energy level.

Apart from using a variety of LED lighting at different places, color changeable LEDs can also be used. Such bulbs change the color and CCT as per the requirements.

Selecting best circadian LED for a facility

Selecting best circadian LED for a facilityAll the LEDs are not crafted equally, but once combined with proper planning and installation, they can provide benefits. Different facility or infrastructure requires different circadian LEDs. Example, highways need the higher light output to help the drivers, same goes for areas near residential areas. Inferior lights around residential areas may result in trespassing. Facility managers are required to work closely with LED companies to decide what kind of lights they need, depending on the facility and its areas. Warm LED lights should be installed only where it is really needed so that it can benefit the Circadian Rhythm, but at the same time do not compromise with the security or comfort.

Circadian lights for homes

Circadian lightsCircadian-effective lights used to be very expensive and difficult to set up. Recently, Philips launched SceneSwitch, LED bulb that is easy to set up, but still the cost is high only if compared to regular bulbs. You just have to screw it in like a regular bulb and power it on. Switch off the light and switch it on again, you will see the light color is changed. Do it for few times and you will understand that you can actually change the colors by just powering it off and on again. It is not only changing colors here but also emitting the light to maintain Circadian Rhythm. You can choose the energetic color in the day with more blue light and dim relaxing color in the evenings.

You can purchase the LEDs from Amazon or from the shopping site of Philips. Pack of four 60W SceneSwitch bulbs comes at $34 (6, 823 INR). Apart from Philips, Wipro offers similar cost-effective solutions. Again, the price may look high but you are spending on your health benefits. Go for it.


We should always desire a better health. By replacing the artificial light with something that can offer health benefits like natural light is giving ourselves a chance to sleep better, feel better and perform better every day.

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