Abstract

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.