The bright side of life – Daytime light exposure and well-being in younger and older adults’ daily lives

Objective: People today spend most of their time indoors which likely results in suboptimal lighting conditions and may negatively impact their health and well-being. However, research on the effects of light exposure in daily life is sparse. In the present work, we address this gap by examining the links between daily light exposure with different well-being indicators. Methods: In the present study, 30 younger (Mage=24.1, SD=3.2, 47% women) and 29 older adults (Mage=67.4, SD=5.16, 59% women) wore a light sensor as a pendant for 10 consecutive days in their daily lives, sampling light exposure every 10 seconds. They reported their momentary positive affect (PA), negative affect (NA), vitality, and alertness up to six times per day. We analyzed associations of light exposure in the previous 5, 60, and 180 minutes with these different aspects of well-being. Results: Multilevel models showed that both brighter overall levels of melanopic equivalent daylight illuminance (mEDI) and longer time spent above 250 lx mEDI were associated with higher high arousal PA, vitality, and alertness but not with lower NA. Additional analyses indicated that for PA and vitality this association may mainly exist for natural daylight whereas the light source did not matter for alertness. Exploratory analyses of higher thresholds (500-750 lx mEDI) partly yielded stronger effects. Conclusion: This pattern of results may suggest energizing and activating effects of light exposure and future research should determine whether light exposure behavior could be a target for interventions to increase health and well-being in daily life.