The Twenty-Fifth Hour

Photo courtesy: ABC News

When I was young, I was fascinated by time travel. Therefore, it should be no surprise that I looked forward to a 25-hour day. Once a year, as the weather gets colder and the sky darkens faster, most North American and European countries “fall back” from daylight savings time (DST). They set their clocks back by one hour, creating an extra hour in the day.

Aside from my excitement for the magical twenty-fifth hour, I never understood the purpose of Daylight Savings—and nor do most Americans, who want it abolished! To many, DST is only a nuisance: forcing you to adapt to an unfamiliar routine, causing scheduling headaches with the rest of the world and disrupting your valuable sleep. 

If Daylight Savings is so useless, then why does it exist, and why do so many want it gone? Furthermore, how much does one hour really matter?

In a nutshell, Daylight Savings is a peculiar system. First suggested in 1784 by Benjamin Franklin, it collectively advances clocks in a country during summer months, and then sets them back as winter approaches. DST’s goal is to better align conventional waking times with daylight hours: because, in the summer, the sun sets later (and vice versa in the winter). 

Sunlight Lovers

According to its proponents, DST allows us to make better use of daylight hours. Some suggest that it conserves energy used to illuminate homes, as natural sunlight can be utilized instead of fuel. Others say that longer daylight hours will reduce crime, car accidents, and even deer collisions. But are these arguments actually true? Let’s find out.

First, does it save energy? No. Although DST was introduced mainly to conserve energy, “little evidence” suggests that it is successful1, 2, 3, 4. Then does it decrease crime? It does: one study shows “a 7% decrease in robberies following the shift to DST. Does it decrease motor accidents? Most data is inconclusive or contradictory 5, 6, so we’re not sure. However, DST is great news if you are a deer — permanent DST would kill “37,000 fewer deer” annually.

Finally, how does it affect sleep and health? According to the American Academy of Sleep Medicine, “daylight saving time is less aligned with human circadian biology,” meaning it makes us more sleep-deprived. This causes significant health and safety risks: an increase in heart attacks, strokes, and seasonal depression, among others.

Ripple Effect

Although most agree that DST is a nuisance, governments remain divided on how to change the system: should we choose a permanent standard or daylight savings time? Standard time better matches our body’s natural rhythms, but more evening daylight boosts commerce and economic growth.

Shifting clock by one hour has resounding effects: killing thousands fewer deer and increasing heart attacks and depression. With or without DST, we should keep in mind how small shifts can change our lives. One hour, it turns out, can change far more than we think.