Impacts of Night Shift on Medical Professionals: A Pilot Study of Brain Connectivity and Gut Microbiota

Tengmao Yao ¹ Yi-Ping Chao ² Chih-Mao Huang ³ Hsin-Chien Lee ⁴ Chi-Yun Liu ¹ Kuan-Wei Li ⁵ Ai-Ling Hsu ⁶ Yu-Tang Tung ^7* Changwei Wu ^1*

• ¹ Graduate Institute of Biomedical Engineering, Graduate Institute of Mind, Brain and Consciousness, College of Humanities and Social Sciences, Taipei Medical University, Taipei, Taiwan
• ² Department of Computer Science and Information Engineering, College of Engineering, Chang Gung University, Taoyuan, Taiwan
• ³ Department of Biological Science and Technology, National Yang Ming Chiao Tung University, Taipei, Taiwan
• ⁴ Graduate Institute of Humanities in Medicine, College of Humanities and Social Sciences, Taipei Medical University, New Taipei, Taiwan
• ⁵ School of Nutrition and Health Sciences, Taipei Medical University, Taipei, Taiwan
• ⁶ Department of Artificial Intelligence, Chang Gung University, Taoyuan, Taiwan
• ⁷ Graduate Institute of Biotechnology, National Chung Hsing University, Taichung, Taiwan

Night shift is a prevalent workstyle in medical hospitals, demanding continuous health monitoring and rapid decision making of medical professionals. Night shifts may cause serious health problems to medical staff, including cognitive impairments, poor sleep, and inflammatory responses, leading to the altered gut-brain axis. However, how night shifts impact gut-brain axis and how long the impact lasts remain to be studied. Hence, we investigated the dynamic changes of brain-microbiota relations following night shifts and subsequent recovery days among medical shift workers. Young medical staffs were recruited for the 3-session assessments over the scheduled night shifts (pre-shift, post-shift, and recovery) by measuring (a) sleep metrics, (b) brain functions, (c) gut bacteriome compositions, and (d) cognitive assessments. Participants experienced partial sleep deprivation only during the 5-day night shifts but rapidly returned to baseline after the 4-day recovery, so as the elevated brain fluctuations in the superior frontal gyrus after night shifts. Meanwhile, the night shifts caused elongated connectivity changes of default-mode and dorsal attention networks without recovery. Nevertheless, we did not find prevailing night-shift effects on cognition and gut bacteriome compositions, except the Gemellaceae concentration and the multi-task performance. Collectively, night shifts may induce prolonged alterations on brain connectivity without impacts on gut bacteriome, suggesting the vulnerable brain functions and the resilient gut bacteriome to the short-term night shifts among medical shift workers.