Application of an Electronic Health Record System for Studying the Influence of the Daylight-Saving Time Change on Health Needs

Daylight-Saving Time (DST) was introduced in Bulgaria on April 1st, 1979. Since 1997, DST begins at 3 a.m. on the last Sunday in March and lasts until 3 a.m. on the last Sunday in October. In 1999, daylight saving time began at 3 a.m. on the last Sunday in March and lasted until 4 a.m. on the last Sunday in October. The original idea of daylight-saving time was focused on saving electricity and using the light part of the day, but as a more serious argument at the moment is the impact of time change on the health of citizens, MEPs decided to stop this practice in 2021 [1] The paper presents data from an Electronic Health Record system (EHR), developed for Central Emergency Help Services in Sofia Municipality, which stores each emergency call on the territory of the district, and for the purposes of the study data were studied and processed as follows: number of emergency calls 1 week before the time change, the week after the time change and one additional week for a two-year period of the system's operation. The results showed an increase of the number of emergency calls on all the days of the first week with a peak on the first and last working days and a decrease in the second week regardless of the season. The results support the decision to cancel the time change due to the fact that it affects the health status of people negatively. (C) 2021 The Authors. Published by Elsevier B.V.