UCL Institute for Environmental Design and Engineering


Lorna Flores Villa

Daylight Effect on Sleep Patterns of People over 65 years old

Funded by Consejo Nacional de Ciencia y Tecnologia (CONACyT), México

Over time, the human’s body clock (circadian clock) has adapted to solar time, when there is light we are supposed to be active and when is dark our body prepares to rest and restore energy. The input of Light and Dark cycle is received by the human eye, depending on the light input (characteristics) it can affect the visual system and the Non-Image Forming system (NIF).

With age the physiology of the human body changes, however, only when it begins to decline people start to notice and make the necessary adjustments to reduce them. It is common that people over 65 years begin to experience physical and psychological deterioration, which might limit their independence, activities and overall health, increasing the demand for healthcare service provision. Due to changes in the physiology of the eye and brain performance, both the visual system and NIF functions are diminished. Older people then start to experience a decrease of contrast sensitivity, visual acuity, colour discrimination, visual field size and glare sensitivity, in combination with diminished dark adaptation and processing visual information. Due to these factors, variation in the circadian rhythmicity becomes more evident for older people, the circadian amplitude diminishes, the circadian phase advances (it starts earlier than environment cues) and the ability to adapt to shift phase is reduced. These modifications have an impact on physiological processes. Distorted sleep/awake patterns are mostly associated with irregular circadian timing, and it may contribute to more health problems.

At least 50% of the elderly population experience sleep disturbances. It has been shown that having bad sleep has unfavourable effects on the human body and performance. Lack of appropriate lighting during daily activities could be amongst the reasons for having bad sleep. Therefore, if people over 65 have sufficient exposure to daylight then they might have better sleep quality, which should positively affect their overall well-being.

The research aim is to observe the relation between daylight exposure and sleep quality reported by the participants over a year, with this information collected it is expected to do an intervention which could led to improve sleep quality on people with sleep disturbances.