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As I write I can hear the chilling notes of the theme song to the classic 1970s horror film, “Halloween” playing in the background. When that movie came out, it had such an impact that we were seeing young patients presenting for psychotherapy for the anxiety and fear that followed viewing it. Something similar had happened a few years earlier with “The Exorcist” (still regarded by many as the scariest movie ever made). I suspect this even happened for the “Wizard of Oz”. Young viewers were frightened by the wicked witch suddenly appearing in the glass globe where Dorothy had just seen her kindly Auntie Em. (I know I was.) This time of year brings all kinds of eerie associations with the festivities surrounding Halloween - the viewing of classic horror movies, the changing of the seasons, the darkening of the evening sky, and the coming of winter. Yes, as any fan of Game of Thrones knows, winter is coming. And, of course, we experience the “falling back” - the change in time that happens in early November. It occurs on November 6th at 2:00 AM this year, to be exact.
It has been a very nice fall in New England this year. The leaves on the trees have changed into the bright colors of autumn and are falling to the ground. We have been having unusual weather in recent years and this year is no different. In New Haven, last week we had an early first snow. And as always in October, we see that the days are getting shorter. We are leaving for work in the dark and going home in the dark as well.
It is this seasonal change that has impressed humans for millennia. It is an important time. In the early societies of northern Europe, being aware of the change in season was vital to survival. You had to know when to store your food and prepare for the winter and when to bring the cattle back from the upland summer feeding pastures. As the days grew shorter, people were also aware that the increasing darkness was reminiscent of the shortness of life and the closeness of death. It’s possible that story telling grew darker in the autumn months, as well. I remember experiencing this myself, when one of my elementary school teachers told us that fall was her favorite season because of the intensity with which everything was living – insects and plants included, aware that the end was near.
In the Celtic lands, Samhain was the festival associated with this particular time of year. Samhain fell about half way between the equinox and the shortest day of the year, and was said to be the time when the boundary between this world and the next was most easily navigated. Spirits could enter our world on this day. The Celts devised various festivities to cope with this situation and win the favor of the spirits. Today many Neopagans and Wiccans observe this day as a religious holiday.
It may be that the church adopted this day and Christianized it by associating it with All Hallows’ Day, when the saints are remembered and honored. So “All Hallows’ Eve” eventually became Halloween. It is thought that in the early second millennium the church was trying to replace the old Celtic Samhain with a church sanctioned holiday to remember the dead, and absorbed some of the old Celtic festivities with costumes, parades, and bonfires. It is also possible that Halloween emerged as a purely Christian holiday. The observance of Halloween came to the “new world” and was especially prevalent in the southern colonies. It was Americanized in the process. The telling of ghost stories, harvest parties, fortune telling and mischief making were part of this growing tradition. The celebration of Halloween gradually spread over the entire United States. By the 1950s the modern version of Halloween had emerged with parties, costumes, and children trick-or-treating. Since the 1970s, Halloween has become a major holiday for adults as well, with parties, ghost walks, extreme candy consumption, and watching really scary horror movies all taking place. Indeed, Halloween has grown into a huge secular event and is the second biggest commercial holiday in the U.S. with billions of dollars of sales of candy and costumes.
As a sleep clinician I am very aware that as Halloween nears, so does a change in how we set our clocks - and this will affect the sleep of at least some of my patients. Daylight Savings Time (DST) will end and Standard Time (ST) will resume less than a week after Halloween. And so Halloween brings with it the time change and seasonal variations that affect sleep.
The history of DST is both long and short. Apparently, even in ancient Rome, adjustments in time keeping were made based on the seasons. Water clocks used different scales depending on the month of the year. Benjamin Franklin suggested, apparently in jest, that getting up earlier and using natural morning light, could save candles. In 1895, George Vernon Hudson, a scientist in New Zeeland, suggested shifting time forward two hours in October and two hours back in March. This idea was, however, never implemented. The first use of DST was in Thunder Bay, Ontario, Canada, in 1908. By 1914 it spread to other locations in Canada and proved to be popular.
Sadly, as with a number of innovations, it was wartime conditions that propelled use of DST forward in a major way. Germany first implemented DST on April 30, 1916, during the First World War in an effort to conserve fuel for the war effort. The UK and France soon followed for the same reason. Robert Garland, an American industrialist, learned of the use of DST in Great Britain during the war and promoted its use in the U.S. It was signed into law by President Woodrow Wilson in 1918, also to support the war effort, after the entry of the U.S. into the war. After that war many countries returned to using ST until the Second World War, when most European countries adopted the use of DST. FDR made its use year round in 1942 when it was called “War Time”. From the end of the war in 1945 until 1966 there were no consistent rules for its use. In 1966 the Uniform Time Act made the last Sunday of April the start of DST and the last Sunday of October the end of it. In response to the oil crisis of 1973, congress extended DST to as much as 10 months of the year. It was found to be effective in reducing the use of oil but was controversial because children were going to school in the dark. The dates for the start and end of DST in the U.S. have changed a number of times since then and DST currently starts on the second Sunday in March and ends on the first Sunday of November. DST has been used by 141 countries at one time or another and is in use by 77, including the U.S., today.
Now, the impact of shifting the clock on sleep has to do with its effect on the circadian (24 hour) rhythm of wakefulness and sleep. In some ways, it is easier to adjust to the “spring forward” time change as most people can pretty easily stay up an hour later than usual. “Falling back” can be more difficult as it is hard to go to bed and fall asleep earlier when you are not yet tired. (You can’t make yourself go to sleep but you can usually force yourself to get up.) This can result in lying awake in bed for longer than usual until you adapt to the change, which can take a few days.
Interestingly, research indicates that it is the spring forward time change that is actually the most challenging. I think many people in our sleep-deprived nation can agree that getting the extra hour of sleep with the change to ST is a welcome thing. Losing the hour with the shift to DST, on the other hand, can be very stressful. Research by Sandhu, Seth, & Gurm, (2014) supported earlier research that had shown an increase in hospital admissions for heart attacks after the shift to DST in the Spring and a decrease right after the shift back to ST in the fall. Sandhu, Seth & Gurm (2014) looked at changes in admission for percutaneous coronary intervention in hospitals in Michigan for the time changes between March 2010 and September 2013. While there were no differences in the total number of coronary interventions performed for heart attacks in either the spring or fall for the full weeks that included the time changes, there was a 24% increase on the Monday following the Spring time change and a 21% reduction on the Tuesday following the change in the Fall. So go ahead and enjoy the Snickers, costumed spooks, and scary movies - the time change that Halloween ushers in is unlikely to give your heart an untimely jolt, and you will be following an ages-old (Celtic? Christian? Pagan?) tradition of celebrating the cycles of life and death, and day and night. And when the celebration’s over, fall back and get a good night’s sleep!
Sandhu, A., Seth, M., & Gurm, H. S. (2014). Daylight savings time and myocardial infarction. Open Heart, 1(1), e000019. http://doi.org/10.1136/openhrt-2013-000019
