After Daylight Savings Time (DST) last weekend, I began to wonder how this changing of time affects one’s physiology. I have always heard that people believe DST causes health conditions and I wanted to research if this is true. One study of 100,000 participants indicted a modest but significant risk of acute myocardial infarction in the weeks following both the spring and fall DST (Manfredini et al., 2019). An additional study argued that incidents of stoke increase by 9% and heart attack incidents increased by 29% (Watson, 2019). The risk, however, was more significant following the spring DST because everyone losses an hour of sleep (Manfredini et al., 2019). Although one hour does not seem substantial, another study found that one hour can disrupt out body’s clock for weeks afterward (Roenneberg, Winnebeck, & Klerman, 2019). This is because DST causes interruptions of one’s circadian rhythm, resulting in disrupted sleep quality and quantity, increased heart rate and blood pressure and increased pro-inflammatory cytokine levels (Manfredini et al., 2019). Furthermore, the science community is beginning to understand that DST can have acute and chronic affects. Some acute affects are mood changes, miscarriages, strokes and sleepier adolescents (Roenneberg et al., 2019). Chronic affects are still being researched but it is thought that the affects are similar to the affects of “shift work schedules” (Roenneberg et al., 2019).
Over the years countries and states have begun to reconsider whether to continue having DST or whether they should start having DST. The question I believe these places/regions should be asking is, whether adopting or keeping DST is doing no harm (nonmaleficence). If there is a modest but significant risk for heart attacks or strokes, is it ethical to require the people of these regions to follow this twice- yearly altered clock? I personally believe that the risks outweigh the good and that Daylight Savings Time should be discontinued because I believe our society should put the health and wellbeing of its people before the prosperity and wealth of our economy. Most of the science community also strongly argues against DST and in particular, sleep health care providers have begun to speak out about their concerns to political leaders. (Roenneberg et al., 2019)(Watson, 2019).
Manfredini, R., Fabbian,
F., Cappadona, R., De Giorgi, A., Bravi, F., Carradori, T., … Manzoli, L.
(2019). Daylight Saving Time and Acute Myocardial Infarction: A Meta-Analysis. Journal
of Clinical Medicine, 8(3), 404. https://doi.org/10.3390/jcm8030404
Roenneberg, T.,
Winnebeck, E. C., & Klerman, E. B. (2019). Daylight saving time and
artificial time zones - A battle between biological and social times. Frontiers
in Physiology, 10(JUL), 1–12.
https://doi.org/10.3389/fphys.2019.00944
Watson, N. F. (2019).
Time to show leadership on the daylight saving time debate. Journal of
Clinical Sleep Medicine, 15(6), 815–817.
https://doi.org/10.5664/jcsm.7822
I am from Arizona, where we do not observe daylight savings time. Personally, I think I have been unaffected by the change in the last few years since I moved to Colorado. It would be interesting to do a study comparing physiological effects like heart rate, blood pressure, and cytokine levels between people in a state that does observe daylight savings, and a state that does not. I would also be curious if the physiological effects observed during the first few days following the time change during daylight savings is comparable to say, traveling from the US to Europe for vacation where an even more intense time shift is experienced.
ReplyDeleteUpon doing some additional research on the topic of circadian rhythms, I found research to help explain the reason for the increased occurrence of acute myocardial infarction and hypertension in the weeks following a time change. According to a study, cardiomyocytes depend on the circadian clock to appropriately utilize fatty acids. Therefore, fatty acids are able to accumulate intracellularly, which can be detrimental since this affects the contractile ability of the heart and increases vascular resistance (Manfredini et al., 2018)
Reference:
Manfredini, R., Fabbian, F., Cappadona, R., & Modesti, P. A. (2018). Daylight saving time, circadian rhythms, and cardiovascular health. Internal and emergency medicine, 13(5), 641–646. https://doi.org/10.1007/s11739-018-1900-4