Influence of cold and light exposure on biological rhythm: HEIJO-KYO cohort study

Dr. Keigo Saeki


Department of Epidemiology

Nara Medical University School of Medicine





佐伯 圭吾 氏






Higher mortality in winter by 10 to 20% than other seasons is a world-wide problem. Paradoxical fact that countries in relatively warm winter climate shows significantly higher increase of mortality in winter than those in sever winter climate suggest necessity to assess indoor environment directly exposed to body. 

Shift workers exposed to light at night shows higher incidence of depression, diabetes, cancer, and cardiovascular disease. However, little is known about the amount of light exposure at night in real life situation and its influence on health. 

I will present some novel findings from the HEIJO-KYO study, a community based cohort study investigating the influence of environmental temperature and light exposure on health. The cohort study conducted among 1127 elderly participants (≧60 years) simultaneously investigated the indoor temperature, light exposure, ambulatory blood pressure, physical activity, and objective sleep quality at participants’ home for 48 hours in winter, and follow the incidence of obesity, depression, cardiovascular disease and cancer. 


In addition, I will show some demands in devise for measuring ambient environment and biological rhythm, and its reason for affinity of MEMS technology to such measurements in terms of disease prevention and health promotion.






Keigo Saeki, MD, PhD, is a Lecturer in the Department of Epidemiology, Nara Medical University School of Medicine. Dr. Saeki earned his MD at Jichi Medical University in 1999, and PhD at Nara Medical University, Japan in 2012. He completed post-graduate training in Nara prefectural hospital, Nara, Japan. He is a fellow of the Japanese Society of Internal Medicine. His primary research interest is in indoor cold exposure that influence the winter excess mortality. Thus, Dr. Saeki’s current special interests include epidemiology related to indoor cold exposure.


・Fellow of the Japanese Society of Internal Medicine (FJSIM)

・Japan Primary Care Association certified family physician



Dr. Saeki graduated from Jichi Medical Univesity school of medicine.






Gold Sponsors

Silver Sponsors

Bronze Sponsors


Regular Exhibitors

Venture Exhibitors

Academia Exhibitors