Researchers at the Rensselaer Polytechnic Institute's Lighting Research Center (LRC) and the U.S. General Services Administration have just published a series of recent findings that explore how light affects alertness during the day and sleep quality at night.
This study tested a special lighting device developed by LRC that could help set sleep-wake cycles and alertness for employees. 19 participants from the U.S. Department of State Office in Washington, DC completed the three-week study.
Time is spent indoors, but the lighting in the room is usually not enough to stimulate the biological clock. Typical office lighting provides less than 100 lux of light to the eyes, and more than 1,000 to 10,000 lux of light outdoors on sunny days. Circadian stimulation (CS) is a measure of the type of light required to affect the body's biochemistry. Rather, it is the type and intensity of the light that inhibits the hormones that make us sleepy. The CS indicator is based on a model proposed by scientists how the retina converts light signals into neural signals of the circadian system, which determines the lighting needed to suppress sleep hormone melatonin. The lighting design goals of the circadian system are different from those of traditional architectural lighting design, so the required indicators are different from those currently used by lighting designers.
The saturated blue light emitted by the lighting equipment installed near the participant's computer display in the morning has a circadian rhythm stimulation of 0.4; the polychromatic white light at noon has a circadian rhythm stimulation of 0.3; the saturated red light in the afternoon has a near-zero circadian rhythm stimulation.
Objective and subjective measures of rest-activity, sleep, vitality and alertness are used to evaluate lighting interventions. The results showed that participants exhibited a more stable rest-activity pattern, suggesting that their sleep-wake cycle or circadian cycle matched the day-night cycle and woke up earlier during the study. Blue light in the morning seems to advance participants' physiological cycles, causing participants to wake up earlier in the morning. The red light in the afternoon caused a strong alert response when the energy dropped after lunch (about 3 pm), reducing drowsiness and increasing subjective vitality and energy.
The results of research in these fields for the first time prove that the combination of red light and ambient white light can provide effective sensory stimulation and support the inference that when light is used properly, it can promote the entrainment of circadian rhythm and improve alertness.
The research paper "Light, Entrainment, and Alertness: A Case Study in the Office" was published in the journal Lighting Research and Technology. Authors include Mariana Figueiro, Mark Rea, Levent Sahin and Charles Roohan.
Previous LRC research measured the light levels of 109 participants in five government office buildings in the United States, which were designed to maximize the use of indoor daylight. Dr. Figueiro and her team found that even in open offices with many large windows, office workers were unable to get enough light to stimulate their day and night due to factors such as seasons, cloud cover, desk orientation, and curtain location Rhythm system.
Based on these findings, the research team speculated that additional artificial lighting could be used to ensure that office workers get enough light during the day, and that 68 participants were equipped with a circadian-regulated lighting system in four other locations. The results showed that the drowsiness of office staff was greatly reduced with the use of additional artificial lighting, and, as assumed, they reported a marked increase in their vitality, energy and alertness.
Current research results show that tailor-made lighting interventions can help inspire building occupants or users and increase alertness during working hours. Dr. Figueiro said that the "non-visual layer of light" used in the current study is not only practical but also low cost, helping to strengthen the bridge between laboratory results and field applications.
Scientists say that most people do not get enough light during the day, but there is too little light during the day and too much light at night. Many people use light-emitting electronic devices such as smartphones and tablets at night, or work late on their computers. When you're ready to sleep, the light from these screens makes your brain think it's time to get up.
The disruption of circadian rhythm affects each of our biological systems, from single-cell DNA repair to melatonin secreted by the pineal gland of the brain. The relationship between circadian and disordered rest activity patterns is most obvious, the latter can cause daytime drowsiness and nighttime insomnia, and is also associated with increased risk of diabetes, obesity, cardiovascular disease and certain cancers.
Exposure to a powerful 24-hour light-dark cycle promotes circadian rhythms, which have many health benefits, such as increased alertness and vitality during the day, improved mood, and improved nighttime sleep. Recent research suggests that healthy, regular sleep patterns may even help prevent Alzheimer's disease.
Researchers at the Rensselaer Polytechnic Institute's Lighting Research Center (LRC) and the U.S. General Services Administration have just published a series of recent findings that explore how light affects alertness during the day and sleep quality at night.
This study tested a special lighting device developed by LRC that could help set sleep-wake cycles and alertness for employees. 19 participants from the U.S. Department of State Office in Washington, DC completed the three-week study.
Time is spent indoors, but the lighting in the room is usually not enough to stimulate the biological clock. Typical office lighting provides less than 100 lux of light to the eyes, and more than 1,000 to 10,000 lux of light outdoors on sunny days. Circadian stimulation (CS) is a measure of the type of light required to affect the body's biochemistry. Rather, it is the type and intensity of the light that inhibits the hormones that make us sleepy. The CS indicator is based on a model proposed by scientists how the retina converts light signals into neural signals of the circadian system, which determines the lighting needed to suppress sleep hormone melatonin. The lighting design goals of the circadian system are different from those of traditional architectural lighting design, so the required indicators are different from those currently used by lighting designers.
The saturated blue light emitted by the lighting equipment installed near the participant's computer display in the morning has a circadian rhythm stimulation of 0.4; the polychromatic white light at noon has a circadian rhythm stimulation of 0.3; the saturated red light in the afternoon has a near-zero circadian rhythm stimulation.
Objective and subjective measures of rest-activity, sleep, vitality and alertness are used to evaluate lighting interventions. The results showed that participants exhibited a more stable rest-activity pattern, suggesting that their sleep-wake cycle or circadian cycle matched the day-night cycle and woke up earlier during the study. Blue light in the morning seems to advance participants' physiological cycles, causing participants to wake up earlier in the morning. The red light in the afternoon caused a strong alert response when the energy dropped after lunch (about 3 pm), reducing drowsiness and increasing subjective vitality and energy.
The results of research in these fields for the first time prove that the combination of red light and ambient white light can provide effective sensory stimulation and support the inference that when light is used properly, it can promote the entrainment of circadian rhythm and improve alertness.
The research paper "Light, Entrainment, and Alertness: A Case Study in the Office" was published in the journal Lighting Research and Technology. Authors include Mariana Figueiro, Mark Rea, Levent Sahin and Charles Roohan.
Previous LRC research measured the light levels of 109 participants in five government office buildings in the United States, which were designed to maximize the use of indoor daylight. Dr. Figueiro and her team found that even in open offices with many large windows, office workers were unable to get enough light to stimulate their day and night due to factors such as seasons, cloud cover, desk orientation, and curtain location Rhythm system.
Based on these findings, the research team speculated that additional artificial lighting could be used to ensure that office workers get enough light during the day, and that 68 participants were equipped with a circadian-regulated lighting system in four other locations. The results showed that the drowsiness of office staff was greatly reduced with the use of additional artificial lighting, and, as assumed, they reported a marked increase in their vitality, energy and alertness.
Current research results show that tailor-made lighting interventions can help inspire building occupants or users and increase alertness during working hours. Dr. Figueiro said that the "non-visual layer of light" used in the current study is not only practical but also low cost, helping to strengthen the bridge between laboratory results and field applications.
Scientists say that most people do not get enough light during the day, but there is too little light during the day and too much light at night. Many people use light-emitting electronic devices such as smartphones and tablets at night, or work late on their computers. When you're ready to sleep, the light from these screens makes your brain think it's time to get up.
The disruption of circadian rhythm affects each of our biological systems, from single-cell DNA repair to melatonin secreted by the pineal gland of the brain. The relationship between circadian and disordered rest activity patterns is most obvious, the latter can cause daytime drowsiness and nighttime insomnia, and is also associated with increased risk of diabetes, obesity, cardiovascular disease and certain cancers.
Exposure to a powerful 24-hour light-dark cycle promotes circadian rhythms, which have many health benefits, such as increased alertness and vitality during the day, improved mood, and improved nighttime sleep. Recent research suggests that healthy, regular sleep patterns may even help prevent Alzheimer's disease.
