The complaints start around the second Sunday in March and the first Sunday in November. If it’s March, we grumble about the hour of sleep we’re robbed of at 2 a.m. If it’s November, we celebrate the extra hour’s return … and then complain about how it gets darker earlier. Personally, I’m on Team March; sure, we lose an hour, but I love ending a workday with the sun still shining—it gives the evening a sense of promise.
But aside from the promotion of nighttime revelry in the spring and autumn snooze time, there’s a more official reason for these mandated time shifts. The purported benefit of daylight saving is that the increased daylight time it provides decreases energy consumption overall. While some have questioned this claim (especially in these energy-gluttonous times), even those who do accept it wonder whether the negative physical effects outweigh the potential rewards. Losing an hour in the spring brings about longer days, but it’s detrimental to our sleep health. Even gaining an hour toys with our well-being more than we realize.
Altering Our Alarm Clocks Alters Our Internal Clocks
Having a handy phrase like “spring forward, fall back” is a great way to remember how to set our clocks, but it doesn’t eliminate confusion completely. Some countries don’t follow the time system, and even if they do, the start and end dates differ depending on the region. Not only does daylight saving’s observance vary by country, it varies even within the United States: Hawaii and Arizona (excluding the Navajo Indian reservation there) don’t follow it, and Indiana jumped on the bandwagon only in 2006. Alaska has tried to jump ship in the past, having passed a bill in the House of Representatives to end the state’s reliance on daylight saving; one of the main reasons Alaska cited for passing the bill was the havoc such changes wreak on people’s physical well-being.
Health-wise, the main controversy when it comes to daylight saving time is its effect on circadian rhythms, a process that the body’s internal clock controls to make sure we wake up with the sun and prepare for bed as it gets darker. These clocks don’t observe daylight saving, either—they continue running based on the advent of light and dark, not on what time it actually is. A 2007 study at a university in Munich found that regardless of daylight saving, people operate on cues from their environment. So even if the clock says it’s 7 a.m., if it’s still dark outside, people will be mentally and physically attuned to nighttime.
Being a night owl or a morning person doesn’t make a difference, either. Studies have shown that people who thrive when the sun goes down have a harder time adjusting to daylight saving in the spring, but when it ends in the fall, the time of day when we operate best has no effect on our ability to adapt.
Gain or Lose an Hour – Either Way, It’s Risky
A host of problems and risks arises when people’s sleep cycles are thrown off. When we lose an hour in the spring, drowsiness and stress increase. And even though we get extra snooze time in the autumn, the shift back to standard time creates more dark hours than light, which makes us feel more tired and leads to higher rates of seasonal affective disorder (SAD).
SAD shares many of its symptoms with depression, so even if people aren’t clinically depressed, being affected by the lack of light makes them start to feel that way. Messing in any way with the body’s chronobiological processes (the mechanisms controlling its circadian rhythms) encourages the effect. A 2008 study published in Sleep and Biological Rhythms looked at suicide rates in Australia from 1971 to 2001. The rates tended to increase at the start and end of daylight saving time, which could mean that even small changes can have major emotional consequences for some people.
