Light plays an essential role in psychobiological and psychophysiological processes,such as alertness.The alerting effect is influenced by light characteristics and the timing of interventions.This meta-analysis is the first to systematically review the effect of light intervention on alertness and to discuss the optimal protocol for light intervention.In this meta-analysis,registered at PROSPERO (Registration ID:CRD42020181485),we conducted a systematic search of the Web of Science,PubMed,and PsyclNFO databases for studies published in English prior to August 2021.The outcomes included both subjective and objective alertness.Subgroup analyses considered a variety of factors,such as wavelength,correlated color temperature (CCT),light illuminance,and timing of interventions (daytime,night-time,or all day).Twenty-seven crossover studies and two parallel-group studies were included in this meta-analysis,with a total of 1210 healthy participants (636 (52％)male,mean age 25.62 years).The results revealed that light intervention had a positive effect on both subjective alertness (standardized mean difference (SMD) =-0.28,95％confidence interval (CI):-0.49 to-0.06,P =0.01) and objective alertness in healthY subjects (SMD =-0.34,95％ CI:-0.68 to-0.01,P =0.04).The subgroup analysis revealed that cold light was better than warm light in improving subjective alertness (SMD =-0.37,95％ CI:-0.65 to-0.10,P =0.007,I2 =26％) and objective alertness (SMD =-0.36,95％ CI:-0.66 to-0.07,P =0.02,I2 =0).Both daytime (SMD =-0.22,95％ CI:-0.37 to-0.07,P =0.005,I2 =74％) and night-time (SMD =-0.32,95％ CI:-0.61 to-0.02,P =0.04,I2 =0) light exposure improved subjective alertness.The results of this meta-analysis and systematic review indicate that light exposure is associated with significant improvement in subjective and objective alertness.In addition,light exposure with a higher CCT was more effective in improving alertness than light exposure with a lower CCT.Our results also suggest that both daytime and night-time light exposure can improve subjective alertness.

Yi-Man Mu;Xiao-Dan Huang;Sui Zhu;Zheng-Fang Hu;Kwok-Fai So;Chao-Ran Ren;Qian Tao

Department of Public Health and Preventive Medicine,School of Basic Medicine,Jinan University,Guangzhou,Guangdong Province,China;Division of Medical Psychology and Behavior Science,School of Basic Medicine,Jinan University,Guangzhou,Guangdong Province,China;Guangdong-Hongkong-Macau Institute of CNS Regeneration,Ministry of Education CNS Regeneration Collaborative Joint Laboratory,Jinan University,Guangzhou,Guangdong Province,China;Guangzhou Regenerative Medicine and Health Guangdong Laboratory,Guangzhou,Guangdong Province,China;Center for Brain Science and Brain-Inspired Intelligence,Guangdong-Hong Kong-Macao Greater Bay Area,Guangzhou,Guangdong Province,China;Neuroscience and Neurorehabilitation Institute,University of Health and Rehabilitation Science,Qingdao,Shandong Province,China;Co-innovation Center of Neuroregeneration,Nantong University,Nantong,Jiangsu Province,China

中国神经再生研究（英文版）

[1]Yi-Man Mu;Xiao-Dan Huang;Sui Zhu;Zheng-Fang Hu;Kwok-Fai So;Chao-Ran Ren;Qian Tao-.Alerting effects of light in healthy individuals:a systematic review and meta-analysis)[J].中国神经再生研究（英文版）,2022(09):1929-1936

Alerting,psychobiological,psychophysiological,alerting,CRD42020181485,healthY

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