Lighting and health

Lighting has the potential to affect the health of people in buildings. This goes beyond the safety aspects of providing enough illumination to see by; lighting affects mood and human circadian rhythms, while poor lighting can, in principle, cause glare, headaches, eyestrain, skin conditions and various types of sight loss. There has been a substantial amount of research carried out recently in these areas, and it is important for designers and building owners and occupiers to be aware of all the aspects in which lighting can affect health, avoid risks, and improve general mood and behaviour. 

Human circadian rhythms can have profound effects on a person’s wellbeing. Research indicates that circadian rhythms are mostly regulated by light exposure, which is generally accepted as the major time cue. The variation of light from day to night helps to properly maintain the circadian cycle in the body, which can determine patterns of alertness, co-ordination, blood pressure, cardiovascular efficiency, and other functions in a 24-hour period. However, exposure to the wrong light at the wrong time can cause circadian disruption, which can have detrimental health and wellbeing effects. It is therefore important to maintain bright light during the day and relative darkness at night. 

Adequate lighting and lighting controls, including the provision of emergency lighting, are essential to enable people to work and move around a building or external site safely. Poor lighting, particularly lighting that causes glare, can give visual discomfort which may result in sore eyes, headaches, and aches and pains associated with poor body posture. 

How we can help: 

BRE experts can investigate potential detrimental effects of lighting schemes on human health and wellbeing and advise lighting designers and building managers on how to maximise the health benefits of lighting while minimising risks. For example, this could include: 

1. Flickering lighting causing flicker related problems such as headaches or epileptic seizures. 
2. Failed lighting resulting in dark and unsafe areas. 
3. Glare from luminaires and other bright surfaces, including reflected glare from glossy finishes, potentially resulting in visual discomfort, eyestrain, headaches, and poor body posture problems. 
4. Inadequate daylight. Providing daylight in buildings is often the best way to achieve the benefits of daytime light in entraining circadian rhythms, resulting in improved health and mood, and reducing lighting energy use. A holistic approach including daylight provision integrated with thermal performance and overall building energy use ought to be adopted, even more so in the context of aiming towards net zero carbon buildings. 
5. Circadian disruption which over time can result in health-related problems such as sleep deficiency, weakened immune system, cardiovascular diseases, diabetes, obesity, depression, or learning and memory difficulties.