Good lighting is essential to an individual’s wellbeing. In healthy individuals, a lack of natural or full-spectrum lighting leads to circadian rhythm disturbances or sleep disorders, which may affect the heart, mental health and other systems in the body. When an individual has a cognitive impairment, light therapy for Alzheimer’s patients and those with dementia is vital to naturally regulating sleep cycles and promoting positive emotional and physical health.
Light and the Brain
Within the brain’s hypothalamus is the suprachiasmatic nucleus (SCN), the part of the brain that Alzheimer’s disease typically affects first. The SCN naturally decreases in cell mass in after an individual is about 80 years old, but the reduction of cells is more pronounced in those with Alzheimer’s disease and the reduction occurs at an earlier age. Scientists believe that the shrinkage may relate to the sleep disorders that individuals may experience as they age.
The brain’s SCN regulates an individual’s circadian rhythms, or internal biological clock. The SCN receives and interprets information from the retinas based on the light signals that the photosensitive cells within it transmit. The SCN then sends the information to the pineal gland in the brain. When it’s dark or the light levels are lower, the pineal gland converts serotonin into melatonin and secretes it. Alternatively, when the eyes see white or blue wavelengths in light—like those found in sunlight—serotonin conversion does not occur.
Using Light Therapy for Alzheimer’s Patients
A January 2013 article in the Journal of Alzheimer’s Disease states that circadian system depends on the timing of light exposure to function well and is the most sensitive to blue, or short-wavelength, light. Scientists found that in the morning, bright light exposure of 1,000 lux or more increases daytime wakefulness, helps patients feel less agitated the evening and promotes nighttime sleep. Bright lights also improved cognitive functions and sleep efficiency, and reduced symptoms of depression. While conducting studies, researchers found that the timing of bright light exposure mattered. Alzheimer’s patients seemed to respond the best with morning light therapy between 8:00 a.m. to 11:00 a.m.
The best light therapy for Alzheimer’s patients provides high circadian stimulation during the day and low stimulation in the evening and night. Optimal daytime levels are 1,000 lux or higher for at least two hours. Daylight from windows, for example, is an effective light source. Keep in mind, however, that daylight levels of brightness lower once an individual is three or four meters away, even on a sunny day. Furthermore, daylight from windows may not be effective if it causes an uncomfortable glare that prompts individuals to close the shades.
At night, lights should not be brighter than 60 lux. Research shows that exposure to red and orange wavelengths are the least disruptive to circadian rhythms in the evening. Scientists also found that low ambient illumination in the form of strips of amber LED lights behind doorframes, along with dim incandescent nightlights in hallways, improved patient stability and reduced the risk of falls at night.
Light therapy for Alzheimer’s and dementia patients helps reduce some of the symptoms of cognitive impairment and improves sleep cycles. In turn, this allows an individual to remain independent for a longer period. The light therapy options that Nature Bright offers mimic natural sunlight, providing the benefits of blue and white wavelengths throughout the year. Browse through Nature Bright’s selection of light therapy products to find the best one for your home or facility.
[Photo from Ministere du Travail, de l'Emploi et de la sante via CC Licence 2.0]