Objectives: Several previous investigations indicate that blue light exposure during the night reduces melatonin secretion, improves vigilance and diminishes sleepiness. Moreover it has been demonstrated that a blue light dose administered in the evening can have a positive effect for shift workers. In the present study the effect of cool LED lighting exposure during daily hours has been investigated in two experiments: self-reported sleep and sleepiness have been assessed prior and post light exposure using a sleep diary and Karolinska Sleepiness Scale (KSS). Methods: In the first investigation (E1) the experimental light condition consisted in a 4000 K LED light and the control condition was the halogen lighting (2800 K); while in the experiment 2 (E2) a 6800 K LED lighting has been compared with a warm 3000 K LED light condition. In both experimental studies the cool light exposure duration was about 1 h and 40 subjects (20 females) were involved. Results: Data from E1 indicated that the experimental light condition had a positive effect on sleep latency who significantly decreased (P = 0.004). In the same vein, data from E2 showed shorter nightime awakenings (P = 0.04) and longer sleep time (P = 0.05) in participants exposed to cool LED lighting. No significant effects were observed on sleepiness self evaluations. Conclusions: The present results go in the direction of a better sleep quality and quantity, indicating a greater stability and continuity of sleep after the exposure to colder light. They also support previous results observed under different lighting conditions.

The effects of LED lighting on sleep and sleepiness

CURCIO, GIUSEPPE;PICCARDI, LAURA;
2016-01-01

Abstract

Objectives: Several previous investigations indicate that blue light exposure during the night reduces melatonin secretion, improves vigilance and diminishes sleepiness. Moreover it has been demonstrated that a blue light dose administered in the evening can have a positive effect for shift workers. In the present study the effect of cool LED lighting exposure during daily hours has been investigated in two experiments: self-reported sleep and sleepiness have been assessed prior and post light exposure using a sleep diary and Karolinska Sleepiness Scale (KSS). Methods: In the first investigation (E1) the experimental light condition consisted in a 4000 K LED light and the control condition was the halogen lighting (2800 K); while in the experiment 2 (E2) a 6800 K LED lighting has been compared with a warm 3000 K LED light condition. In both experimental studies the cool light exposure duration was about 1 h and 40 subjects (20 females) were involved. Results: Data from E1 indicated that the experimental light condition had a positive effect on sleep latency who significantly decreased (P = 0.004). In the same vein, data from E2 showed shorter nightime awakenings (P = 0.04) and longer sleep time (P = 0.05) in participants exposed to cool LED lighting. No significant effects were observed on sleepiness self evaluations. Conclusions: The present results go in the direction of a better sleep quality and quantity, indicating a greater stability and continuity of sleep after the exposure to colder light. They also support previous results observed under different lighting conditions.
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Utilizza questo identificativo per citare o creare un link a questo documento: https://hdl.handle.net/11697/113406
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