Seasonal Affective disorder (SAD)

Seasonal Affective disorder or SAD is strongly related to seasonal changes and influences our circadian rhythm. SAD or commonly referred to as winter depression, is a mood disorder caused by the lack of light. It causes feelings of depression, and sleep disturbance.

Access to sufficient daylight is essential for humans and it is increasingly scarce as people spend 80% of their day indoors. Well-planned  interior lighting can reduce the causes of SAD and support wellbeing. Most office spaces for example are illuminated to standards with 500lx or less. Since Daylight has easily 10x as much, spending most of the day indoors does not make it possible to satisfy the need for daylight. With higher artificial light levels, this need for light can be compensated for, leaving people to feel more energised and sleep better at night. In addition,  lighting can follow the colour temperature of daylight (crisp white at noon, and warmer lighting in the morning and late afternoons)  thus supporting our natural  circadian rhythm. There are many lighting fixtures with dynamic or tunable white lighting technology to answer the need for light. Office lighting becomes part of light therapy increasing people's well-being in indoor spaces.