Daylight Savings Time Can Have Adverse Effects On Health

Daylight saving time has been around for over 100 years now, even though there isn’t a shred of evidence that it does what it was intended to do, which is to save energy. Instead, there is mounting evidence that it’s actually detrimental to the health and well-being of people.

According to Science Based Medicine, the most frequently cited evidence for the energy savings due to DST is a 2008 report to Congress by the Department of Energy which showed that total electricity savings from the extended daylight saving period that began in 2007 amounting to 0.03 percent of electricity consumption over the year, which is a minuscule amount of savings. In contrast, a California Energy Commission study after the extension of DST in 2007 found that the estimated weather- and lighting-corrected energy savings from the extended DST was 0.18%, but the confidence interval ranged from a ranging from a 1.5% savings to a 1.4% increase.

So what’s the point when we all suffer trying to readjust to the new time for days after we “spring forward?” Here’s one example of a concern thanks to daylight savings time:

 Multiple studies show that there are more motor vehicle collisions the Monday after the time change to DST. For instance, in 1996, Canadian researchers noted that the number of traffic accidents rose significantly:

The loss of one hour’s sleep associated with the spring shift to daylight savings time increased the risk of accidents. The Monday immediately after the shift showed a relative risk of 1.086 (95 percent confidence interval, 1.029 to 1.145; ξ2 = 9.01, 1 df; P<0.01). As compared with the accident rate a week later, the relative risk for the Monday immediately after the shift was 1.070 (95 percent confidence interval, 1.015 to 1.129; ξ2 = 6.19, 1 df; P<0.05). Conversely, there was a reduction in the risk of traffic accidents after the fall shift from daylight savings time when an hour of sleep was gained. In the fall, the relative risk on the Monday of the change was 0.937 (95 percent confidence interval, 0.897 to 0.980; ξ2 = 8.07, 1 df; P<0.01) when compared with the preceding Monday and 0.896 (95 percent confidence interval, 0.858 to 0.937; ξ2 = 23.69; P<0.001) when compared with the Monday one week later. Thus, the spring shift to daylight savings time, and the concomitant loss of one hour of sleep, resulted in an average increase in traffic accidents of approximately 8 percent, whereas the fall shift resulted in a decrease in accidents of approximately the same magnitude immediately after the time shift.

There is evidence of a small but real increase in heart attacks after “springing forward” too. Swedish data suggests that the risk of myocardial infarction is significantly elevated for the first three weekdays after the transition to DST. A 2013 study in The American Journal of Cardiology found a similar result, with an increase in heart attack rates the Sunday after the shift to DST. Similarly, a recent University of Alabama study found that heart attacks increase by 10-24% on the Monday following the shift to DST. A recent review of the literature published in European Review for Medical and Pharmacological Sciences concluded that transitions into and out of Daylight Saving Time (DST) may disrupt circadian rhythms and lead to sleep disturbance and deprivation.

As we are learning, sleep is important, and Americans, being chronically sleep deprived year round, are especially vulnerable to even minor disruptions in sleep, such that even a disruption as seemingly minor as the spring transition to DST and its associated “loss” of an hour can have ripple effects on health that we have been beginning to appreciate over the last decade or so.