Regular Late Bedtime Significantly Affects the Skin Physiological Characteristics and Skin Bacterial Microbiome

Li Shao,1 Sujing Jiang,1 Yan Li,2 Yanqin Shi,1,3 Man Wang,4 Ting Liu,1 Suzhen Yang,2 Laiji Ma1,3 1School of Perfume and Aroma Technology, Shanghai Institute of Technology, Shanghai, People’s Republic of China; 2R&D Innovation Center, Shandong Freda Biotech Co., Ltd, Jinan, Shandong, People’s Republic of China; 3The Oriental Beauty Valley Research Institute, Shanghai Institute of Technology, Shanghai, People’s Republic of China; 4Department of Nutrition, Shanghai Jiao Tong University Affiliated Sixth People’s Hospital South Campus, Shanghai, People’s Republic of ChinaCorrespondence: Laiji Ma, School of Perfume and Aroma Technology, Shanghai Institute of Technology, No. 100, Haiquan Road, Fengxian District, Shanghai, 201418, People’s Republic of China, Email laijima_sh@163.com Suzhen Yang, R&D Innovation Center, Shandong Freda Biotech Co., Ltd, No. 888, Xinluo Street, Lixia District, Jinan, Shandong, 250101, People’s Republic of China, Email 85844202@qq.comBackground: Late bedtime is a common form of unhealthy sleep pattern in adulthood, which influences circadian rhythm, and negatively affects health. However, little is known about the effect of regular late bedtime on skin characteristics, particularly on skin microbiome.Objective: To investigate the changes and effects of the regular late bedtime on skin physiological parameters and facial bacterial microbiome of 219 cases of Chinese women aged 18– 38 years living in Shanghai.Methods: Based on the Self-Evaluation Questionnaire, bedtime was categorized as 11:00 PM; thus, the volunteers were divided into early bedtime group (S0) and late bedtime group (S1). The physiological parameters of facial skin were measured by non-invasive instrumental methods, and the skin microbiome was analyzed by 16S rRNA high-throughput sequencing.Results: The skin physiological parameters of the late bedtime group exhibited significant decrease in skin hydration content, skin firmness (F4) and elasticity (R2), while TEWL, sebum and wrinkle significantly increased. The result indicated that late bedtime significantly impaired the integrity of skin barrier, damaged skin structure, and disrupted water–oil balance. Furthermore, the analysis of α-diversity, Sobs, Ace and Chao index were found to significantly decrease (P < 0.05) in the late bedtime group, suggesting that late bedtime reduced both the abundance and the diversity of facial bacterial microbiota. Moreover, the abundance of Pseudomonas increased significantly, while Streptococcus, Stenotrophomonas, Acinetobacter, Haemophilus, Actinomyces and Neisseria decreased significantly. In addition, Spearman correlation analysis revealed strong correlations between the microbiota and the physiological parameters. Notably, the abundance of Pseudomonas significantly positively correlated with skin firmness and elasticity, but significantly negatively correlated with skin hemoglobin content, melanin content and skin hydration.Conclusion: Bedtime is an important factor in maintaining skin health. Regular late bedtime not only damages the skin barrier and skin structure but also reduces the diversity and composition of facial bacterial microbiome.Keywords: sleep, late bedtime, skin biophysical property, skin barrier, skin microbiota