A higher illuminance reduces momentary exhaustion in exhausted employees: results from a field study

Research has shown that light can induce alertness-enhancing effects during daytime and at nighttime or in the late evening. Yet, the literature is inconclusive and reported effects are typically modest. It also remains unclear if and how these acute effects of light extend to specific momentary experiences related to burnout in healthy populations. We aimed to investigate whether exposure to a higher illuminance (averaged over the last 60 min) decreases subsequent momentary experiences related to burnout (exhaustion, boredom, and a lack of feeling positively challenged) and whether these relationships differ in those scoring high vs. low on trait burnout. Fifty healthy employees participated in a seven-day ecological momentary assessment study with seven notifications for experience sampling per day and person-worn sensors to monitor and quantify luminous exposure close to eye level. Results showed that when individuals were exposed to a higher hourly illuminance compared to their personal average exposure during working moments, subsequent experiences of momentary exhaustion were lower. In contrast, fluctuations in hourly illuminance were not significantly related to momentary experiences of boredom and feeling positively challenged within participants. The relation between illuminance and subsequent levels of momentary exhaustion was particularly pronounced in persons who experienced relatively high levels of trait exhaustion. This suggests that while adequate lighting is important for all employees, a higher illuminance might be needed for employees regularly suffering from burnout-related symptoms to alleviate their feelings of exhaustion. Although the association was modest, increasing the intensity of office lighting may be a low-obtrusive strategy to reduce experiences related to exhaustion in the moment.