Let’s explore the death and destruction that semi-annual ritual of changing our clocks is implicated.

Stroke.

A study by Finnish researchers, Daylight Saving Time Transitions, Incidence and In-Hospital Mortality of Ischemic Stroke,  found a disturbing pattern of Ischemic Stroke incidence as it relates to the annual switch to Daylight Saving Time. Ischemic Stroke is the most common type of stroke, about 87% of all cases, and in the days immediately following the switch to Daylight Saving Time, they found an 8% increase in the incidence of this type of stroke and for some reason, women were more likely than men to be affected

As is often the case, the news is even worse for those parts of the population that are already compromised is some way. People with cancer have a 25% greater rate of ischemic stroke immediately following the switch to Daylight Saving Time.  The researchers also found that people over 65 are also in danger, with a 20% higher risk.

Heart Attack

A study using hospital data from two hospitals in Michigan, found a similar effect as it relates to myocardial infarction (heart attack). In this study, Incidence of Myocardial Infarction With Shifts to and From Daylight Savings Time, researchers identified a 17% increase in the incidence of myocardial infarction on the day after the switch to Daylight Saving Time.

A different study in Michigan, Daylight savings time and myocardial infarction, found a similar increase of Acute Myocardial Infarction, 29%, immediately following the shift to Daylight Saving Time, but they also found a drop of 21% immediately after the switch back.

Italian researchers conducted a meta-study (a study of studies), Daylight saving time, circadian rhythms, and cardiovascular health, and found a consistent and significant increase in the incidence of myocardial infarction on the Monday following the shift to Daylight Saving Time ranging between 4% and 29%.

While Daylight Saving Time is an inconvenience for most of us, for the part of our population most at risk, the dangers of switching to Daylight Saving Time are a matter of life and death.

SOURCES:
Daylight Saving Time Transitions, Incidence and In-Hospital Mortality of Ischemic Stroke. Jussi O. Sipilä, Jori Ruuskanen, Päivi Rautava, Ville Kytö. Neurology Apr 2016, 86 (16 Supplement)

Daylight savings time and myocardial infarction. Sandhu A, Seth M, Gurm HS Daylight savings time and myocardial infarction Open Heart 2014;1:e000019. doi: 10.1136/openhrt-2013-000019

Incidence of Myocardial Infarction With Shifts to and From Daylight Savings Time. Jiddou, Monica R. et al. American Journal of Cardiology , Volume 111 , Issue 5 , 631 – 635

Daylight saving time, circadian rhythms, and cardiovascular health. Manfredini, R., Fabbian, F., Cappadona, R. et al. Intern Emerg Med (2018) 13: 641. https://doi.org/10.1007/s11739-018-1900-4