Abstract
The purpose of the study was to investigate seasonal variation in mood and behavior among a group of office workers in Sweden (56°N). Thirty subjects participated in this longitudinal study. The subjects kept a weekly log that included questionnaires for ratings of psychological wellbeing and daily sleep-activity diaries where they also noted time spent outdoors. The lighting conditions in the offices were subjectively evaluated during one day, five times over the year. There was a seasonal variation in positive affect and in sleep-activity behavior. Across the year, there was a large variation in the total time spent outdoors in daylight. The subjects reported seasonal variation concerning the pleasantness, variation and strength of the light in the offices and regarding the visibility in the rooms. Finally, the subjects spent most of their time indoors, relying on artificial lighting, which demonstrates the importance of the lighting quality in indoor environments.
Highlights
Seasonal variation in various aspects of human physiology, neuroendocrine function and behavior is quite common [1,2,3,4,5,6,7,8,9,10]
In accordance with other studies, the results suggest that the participants were exposed to more short-wavelength light radiation in the summer and may have experienced a seasonal variation in spectral composition of the light exposure, with higher relative contribution of short-wavelength light radiation, especially in morning and evening, in the summer compared with the winter, spring and autumn [8, 41]
The study confirmed results from earlier studies investigating light exposure in real working and living environments, carried out at latitudes between 30–45°N, showing that many people spend most of their time indoors receiving bright light for relatively short periods during winter and during spring, summer and autumn [40, 73]
Summary
Seasonal variation in various aspects of human physiology, neuroendocrine function and behavior is quite common [1,2,3,4,5,6,7,8,9,10]. The extent to which different light sources were used in the home environment was investigated by the use of a questionnaire that was developed for the study where the subjects indicated if a presented light source was used in most luminaires, in several luminaires, in a few luminaires or not at all. This questionnaire was answered at three occasions, in February, June and January.
Sign-in/Register to view highlights & summary Sign-in/Register to access full text options 
Free) 
Talk to us
Join us for a 30 min session where you can share your feedback and ask us any queries you have
Schedule a call
