The daylight-saving time change will force most of us to spring forward and advance our clocks one hour. This effectively moves an hour of daylight from the morning to the evening, giving us those long summer nights. But waking up Monday morning may not be so easy, having lost an hour of precious sleep and perhaps driving to work in the dark with an extra jolt of java. How time changes actually affect you depends on your own personal health, sleep habits, and lifestyle.
By Dr. Mercola
Daylight Saving Time (DST), the practice of moving clocks ahead one hour in the summer months and returning them back an hour in the winter, was first implemented by Germany during World War I, as a way to conserve electricity.
The idea, however, dates back to William Willett, an Englishman who campaigned for “summer time” in the early 1900s so that people would have more time to be out in the sunlight – though the British government was not interested.
It wasn’t until 1918 that Daylight Saving came to the US, although it was repealed a short time later, in 1919 (largely due to lobbying from the agricultural industry, whose schedules were unproductively disrupted). As reported by History:
“Rather than rural interests, it has been urban entities such as retail outlets and recreational businesses that have championed daylight saving over the decades.”
After the 1919 repeal, there was chaos in the US, with some cities and states continuing to shift their clocks while others did not. In 1966, the Uniform Time Act was passed, which put into place the DST standard used in the US today (although certain states, namely Hawaii and Arizona, opt out).
Since the beginning, DST has been surrounded by controversy, with many arguing against it even to this day. There is reason to believe that not only does DST not conserve energy, but it may actually be putting the health of modern-day humans at risk.
Daylight Saving Time Linked to Increased Risk of Heart Attacks
The first Monday after Daylight Saving Time begins each March is met with grumbles across the US, as most lose one precious hour of sleep. This might seem inconsequential, but research is mounting showing that even slight changes to your circadian rhythm (sleep-wake cycle) can be detrimental to your health… yes, even tweaking it by just one hour.
Recent research presented at the annual scientific sessions of the American College of Cardiology revealed that the risk of having a heart attack on the Monday following DST rose by 25 percent compared to other Mondays.
At the end of the summer, when clocks are turned back one hour so that people get an extra hour of sleep, the risk of heart attack fell by 21 percent. Past research has similarly shown that the disruption to sleep schedules triggered by DST may pose a risk to your heart:
- Research published in the March 2013 edition of the American Journal of Cardiology showed a small rise in heart attack rates the Sunday following the shift to DST, along with a small tick downward the Sunday following the change back to standard time.
- A 2012 University of Alabama study found that heart attacks increased by 10 percent on the Monday and Tuesday following the time change to DST. Heart attacks again decreased by 10 percent on the first Monday and Tuesday after clocks are switched back in the fall.
- A 2008 Swedish study found your chances of having a heart attack increase in the first three weekdays after the switch to DST, and decrease after you set your clock back to standard time in the fall. Heart attacks increase by five percent the first Monday after the time change, and 10 percent on Tuesday.
Moving our clocks in either direction changes the principal time cue — light — for setting and resetting our 24-hour natural cycle, or circadian rhythm. In doing so, our internal clock becomes out of sync or mismatched with our current day-night cycle. How well we adapt to this depends on several things.