We explore the connection between equity returns and sleep disruptions following daylight-savings time changes. In international markets, the average Friday-to-Monday return on daylight-savings weekends is markedly lower than expected, with a magnitude 200 to 500 percent larger than the average negative return for other weekends of the year. This ``daylight-savings anomaly'' in financial markets is consistent with desynchronosis research which has identified the effects of changes in sleep patterns on judgment, anxiety, reaction time, problem solving and accidents. This paper suggests sleep effects of daylight-savings time changes may be impacting market participants internationally.

https://papers.ssrn.com/sol3/Delivery.cfm/000210303.pdf?abstractid=208623&mirid=1

Losing Sleep at the Market: The Daylight-Savings Anomaly

The authors gratefully acknowledge the
financial support of the Social Sciences and Humanities
Research Council of Canada.

/pdf/losing-sleep-at-the-market-the-daylight-saving-anomaly-ktp3sfx7kl.pdf

Losing Sleep at the Market: The Daylight Saving Anomaly

The authors examine the differential influence of time changes associated with Daylight Saving Time on sleep quantity and associated workplace injuries. In Study 1, the authors used a National Institute for Occupational Safety and Health database of mining injuries for the years 1983-2006, and they found that in comparison with other days, on Mondays directly following the switch to Daylight Saving Time-in which 1 hr is lost-workers sustain more workplace injuries and injuries of greater severity. In Study 2, the authors used a Bureau of Labor Statistics database of time use for the years 2003-2006, and they found indirect evidence for the mediating role of sleep in the Daylight Saving Time-injuries relationship, showing that on Mondays directly following the switch to Daylight Saving Time, workers sleep on average 40 min less than on other days. On Mondays directly following the switch to Standard Time-in which 1 hr is gained-there are no significant differences in sleep, injury quantity, or injury severity.

/pdf/changing-to-daylight-saving-time-cuts-into-sleep-and-1z03r3031p.pdf

Changing to daylight saving time cuts into sleep and increases workplace injuries.

The incidence of acute myocardial infarction was significantly increased for the first 3 weekdays after the transition to daylight saving time in the spring. In contrast, in the autumn, only the first weekday was affected significantly.

Shifts to and from Daylight Saving Time and Incidence of Myocardial Infarction

The impact of daylight saving time on sleep and related behaviours

The frequency of traffic accidents for the State of California for the week preceding and the week subsequent to the fall and spring DST changes were analyzed for the years 1976, 1977, and 1978. Regardless of season of the year, DST change was associated with a significant increase in traffic accidents during the post-change weeks.

Daylight Saving-Time Changes Increase Traffic Accidents:

A mild hypothermia was produced in female rats during treatment with pyridoxine HCl (Vitamin B6), 100 mg/kg, administered in the drinking water. The hypothermic effect appeared by day 3 and persisted through 15 days of treatment. The reduction in core temperature was greater early in the day, just following the nocturnal period of maximum food and water consumption of the rat. Tail tendon temperatures of control and pyridoxine-treated animals showed no evidence of increased heat loss. Thus the hypothermia appears to reflect decreased heat production. The implications of a reduced metabolic rate for gerontological research are discussed.

Kristin A. Lindseth

Papers

Daylight Saving-Time Changes Increase Traffic Accidents:

Pyridoxine reduces core body temperature in rats.