Aging, Sleep Disturbance, and the Body Clock

Using Light Therapy to Correct Age Related Sleep

As people age the internal body clock that coordinates human physiology with the 24-hour day weakens. Older people tend to get tired earlier and wake up earlier. Sleep problems which commonly trouble the elderly aren't just an annoyance. Lack of sleep can impair memory, disrupt metabolism, and perhaps even hasten death. Refs.

People in their 60s and 70s often find themselves getting tired at 5:00 or 6:00 PM, and then awaken at 2:00 or 3:00 AM. Many restaurants have "seniors" supper specials starting at 3:00 or 4:00 p.m. to accommodate older customers. When people reach their 70s and 80s their circadian rhythms can flatten out, and some lose the ability to maintain a functional sleep-wake cycle. This is most noticable in long term care facilities where residents can be found asleep at any hour of the day or night, and often sleep for a portion of every hour during the day and night. Refs

Light Therapy to Normalize Sleep Patterns

Studies indicate light therapy can remedy early rising syndrome in the elderly by shifting the body clock to a normal nighttime sleeping schedule. Elderly people with fragmented sleeping patterns may also benefit from light therapy, which appears to improve the amplitude of circadian rhythms in the elderly and consolidate sleep at night. Studies indicate that light therapy can help older people stay more alert during the daytime, and reduce or prevent the "night wandering" that complicates the care of many elderly people with Alzheimer's or other forms of dementia. Refs Studies also indicate the reduction of circadian rhythm disturbance through the use of light therapy can result in an improvement in the cognitive state and quality of life in early-stage Alzheimer's-type dementia. Refs.

Physiological changes occur in the eye with aging. The lens of the eye progressively yellows after age 40, which limits the amount of blue light reaching the retina. The extent of blue light filtering by the yellowing lens continues to increase with age. Increased cloudiness of the lens and cornea that occurs with age also causes increased glare from "bright light" or "blue Light" therapy lamps, and most elderly people find exposure to these lamps difficult to tolerate. Ref Additionally, the sophisticated repair system that protects the retina from oxidative damage induced by blue light exposure diminishes with age.

Exposure to bright light therapy lamps, particularly the blue wavelengths of light that reach the retina from these bright light or blue light therapy lamps increases the risk of retinal damage and blindness. The hazard from bright light is compounded because most elderly people have significant retinal damage, and many are taking photosensitizing medications. By age 75 a significant number of people have vision problems from Age-related Macular Degeneration (AMD), and this proportion increases with age.
More on age-related eye damage from bright light

Low intensity Lo-LIGHT therapy lamps are as effective as bright light for regulating the human body clock, and emit no blue light. The GreenLIGHT technology used in Lo-LIGHT lamps provides a safe and comfortable light that is not selectively filtered out by the yellowing lens, maintains its effectiveness and is more easily tolerated by older people. Refs. Lo-LIGHT lamps can be used safely by people with glaucoma or existing retinal damage and anyone who can safely tolerate normal indoor lighting.